Avocado Fruit And it's Benefits

Avocado

Did you know that avocado is a rare fruit? Based on my experience, yes it is. Avocado trees can only bear fruits once a year. Here in my country, Avocado trees are not so many,that's why we called it a rare fruit.

This fruit was also contained some rare nutrients, and here are the list of the nutrients that can be obtain to our body by eating the avocado fruit.

1. Pantothenic Acid

        Pantothenic acid (also known historically as vitamin B5) is among the most important of the B vitamins for the basic processes of life while also being one of the less likely nutrient deficiencies.
One factor helping to prevent pantothenic acid deficiency is its common presence in so many different foods. In fact, the common presence of pantothenic acid in foods is referred to in the naming of this vitamin, since the word pantothen in Greek translates as "on all sides" or "from all "quarters." Among our 100 core WHFoods, 99% contain some measurable amount of pantothenic acid! (Only one of our foods lacks pantothenic acid, and that food is olive oil. While olives themselves contain a small amount of this vitamin, this small amount is lost when the oil is pressed out of the olives since the oil is 100% fat and pantothenic acid is a water-soluble vitamin.)

Without pantothenic acid, you would be unable to use fats, carbohydrates, or proteins as energy sources. You would also be unable to make hormones and your immune system would collapse. These are only some of the important functions that pantothenic acid has.

2. Fiber

          fiber offers a healthy and effective way to stay regular. But that’s not the only reason why we should be including more in our diets. Many different studies have highlighted how eating a diet high in fiber can boost your immune system and overall health, and help you look and feel your best. Some of the benefits include:

Digestive health.

 Let’s get this one out of the way first. Dietary fiber normalizes bowel movements by bulking up stools and making them easier to pass. This can help relieve and prevent both constipation and diarrhea. Eating plenty of fiber can also reduce your risk for diverticulitis (inflammation of the intestine), hemorrhoids, gallstones, kidney stones, and provide some relief for irritable bowel syndrome (IBS). Some studies have also indicated that a high-fiber diet may help to lower gastric acid and reduce your risk for gastroesophageal reflux disorder (GERD) and ulcers.

Heart disease. Fiber, particularly soluble fiber, is an important element of any heart-healthy diet. Eating a diet high in fiber can improve cholesterol levels by lowering LDL (bad) cholesterol. A high fiber intake can also reduce your risk for metabolic syndrome, a group of risk factors linked to coronary heart disease, diabetes, and stroke. Fiber can help to lower blood pressure, reduce inflammation, improve levels of HDL (good) cholesterol, and shed excess weight around the abdomen.

Diabetes. A diet high in fiber—particularly insoluble fiber from cereals—can lower your risk for type 2 diabetes. If you already have diabetes, eating soluble fiber can slow the absorption of sugar and improve your blood sugar levels.

Cancer. There is some research that suggests eating a high-fiber diet can help prevent colorectal cancer, although the evidence is not yet conclusive. Diets rich in high-fiber foods are also linked to a lower risk for other common digestive system cancers, including stomach, mouth, and pharynx.

Skin health. When yeast and fungus are excreted through the skin, they can trigger outbreaks or acne. Eating fiber, especially psyllium husk (a type of plant seed), can flush toxins out of your body, improving the health and appearance of your skin.

Fiber and weight loss

As well as aiding digestion and preventing constipation, fiber adds bulk to your diet, a key factor in both losing weight and maintaining a healthy weight. Adding bulk can help you feel full sooner. Since fiber stays in the stomach longer than other foods, that feeling of fullness will stay with you much longer, helping you eat less. High-fiber foods such as fruits and vegetables tend to be low in calories, so by adding fiber to your diet, it’s easier to cut calories.

There are other ways that a high fiber intake can aid weight loss. By regulating your blood sugar levels, it can help maintain your body’s fat-burning capacity and avoid insulin spikes that leave you feeling drained and craving unhealthy foods. Eating plenty of fiber can also move fat through your digestive system at a faster rate so that less of it can be absorbed. And when you fill up on high-fiber foods such as fruit, you’ll also have more energy for exercising.

Tips for adding fiber to your diet

Depending on your age and gender, nutrition experts recommend you eat at least 21 to 38 grams of fiber per day for optimal health. Research suggests that most of us aren't eating half that amount.

While hitting your daily target may seem overwhelming at first, the following tips can help you easily add more fiber into your diet. By filling up on whole grains, vegetables, and fruits, you can get most of the fiber you need to start reaping the health benefits.

3. Vitamin K

         Vitamin K is named after the German word for blood clotting (koagulation). In fact, this is probably the most common connection that people make with vitamin K—they associate this vitamin with the process of blood clotting. We'll explain more about this function of vitamin K in our "Role in Health Support" section below. However, it's important to know that vitamin K makes a variety of unique contributions to our health, and our knowledge about these contributions has been expanding in new and unexpected ways.

There are three basic types of vitamin K. Their common names are K1, K2, and K3.

The K1 form of vitamin K is found in plant foods, and 44 of our WHFoods are plant foods that serve as excellent, very good, or good sources of vitamin K! Many of our best sources of this vitamin are green vegetables (including 16 excellent sources); this makes good sense since K1 is required for green plants to conduct the process of photosynthesis. The K2 form of vitamin K is made from K1 and K3 by bacteria and other microorganisms. It can also be made in the human body through a conversion process involving K1 and K3.

In plant foods, you won't find much preformed K2, unless those plant foods have been fermented or otherwise transformed by bacteria or other microorganisms. Certain microorganisms can convert K1 into K2. A great example is Bacillus natto. This bacterium can convert K1 into K2 and it is often used in the production of fermented soy products. In fact, this practice is so common that you will sometimes find the word "natto" being used to refer to these foods. Fermented soy foods on our WHFoods list—including tempeh and miso—can contain significant amounts of K2. (And as plant foods, they also naturally contain K1.) Most of our WHFoods animal foods also contain K2, although the amounts are relatively small and insufficient to qualify them as excellent, very good, or good sources of vitamin K.

A third type of vitamin, found preformed in food but in very small amounts, is menadione, or vitamin K3. We don't yet have good research on the health role of these small of K3 amounts in food.

Role in Health Support

Blood Clotting

As mentioned in the Description section, vitamin K is perhaps best known for its role in the blood clotting process. When people hear the term "blood clot," they might sometimes jump to the conclusion that a blood clot is bad. But there are many times when it is very important for our blood to clot. For example, blood clots are necessary to stop bleeding when our skin gets punctured.

Yet at the same time, people are correct when they say that blood clotting can cause problems. For example, if the inside of a blood vessel has become too narrow due to the buildup (over time) of plaque, this plaque can sometimes rupture and our body may form a blood clot in order to seal off the ruptured plaque. However, this blood clot might also end up stopping the flow of blood through the blood vessel since the blood vessel had become overly narrowed from the buildup of plaque.

Regardless of the specific situation, vitamin K is necessary for blood clots to form. The clotting process is very complex, requiring at least 12 proteins to function before the clotting process can be completed. Four of these protein clotting factors require vitamin K for their activity.

Luckily, we rarely see vitamin K deficiency lead to impairment in the clotting process in adults. We see it in newborns because vitamin K does not efficiently cross the placenta to the fetus, and it can take several weeks for the fetus to build up dietary stores. We also occasionally see clotting problems related to vitamin K deficiency in persons with severe liver or gastrointestinal diseases. But vitamin K deficiency basically never causes insufficient clotting disorders in healthy adults.

In contrast to insufficient clotting in healthy adults, we do see vitamin K deficiency becoming involved in unwanted clotting. This process once again involves the activity of multiple vitamin K-dependent enzyme systems, most importantly a system called matrix Gla protein.

It is currently somewhat of an open question how important vitamin K is to the progression of clot formation and heart disease. Researchers have sometimes, but not consistently, been able to correlate low vitamin K intake with increased risk of heart disease.

One problem in interpreting this research, however, is separating out the effect of healthy foods from the nutrients they contain. Even casual readers of this site are probably aware that the same green leafy vegetables that are our richest sources of vitamin K1 are also among the best sources of many other heart-protecting nutrients. Included in this heart-protective list from green leafy vegetables would be the vitamins A (in the form of carotenoids), C, E and B6, the minerals potassium and magnesium, and dietary fiber.

Researchers have attempted to answer this question by giving vitamin K in pill form at amounts similar to those found in the diet. Over a three-year period, 500 mcg of vitamin K—about the amount found in one serving of mustard greens—was associated with slightly slower progression of hardening of the arteries of the heart.

Given the preliminary and somewhat contradictory nature of this research, we would characterize the association between diets high in vitamin K and protection against coronary artery disease to be plausible, but still unproven.

Bone Health

Vitamin K is a fascinating nutrient with respect to bone health, and unlike some of the open-ended questions related to clotting, knowledge about the role of vitamin K nourishment in bone support is fairly well-established. Individuals who are vitamin K deficient have repeatedly been shown to have a greater risk of fracture. In addition, for women who have passed through menopause and have started to experience unwanted bone loss, vitamin K has clearly been shown to help prevent future fractures.

Bone support involves different forms of vitamin K

Research has shown that our bone cells take up vitamin K in the form of K1 as well as K2, suggesting that these forms of the vitamin may play different roles in the health of our bone. In the case of K2, researchers have also become interested in two particular subtypes of K2 called MK-4 and MK-7, which appear to be up taken by our bone cells in preference to other subtypes. In fact, research on bone health is partly responsible for getting researchers more and more interested in the whole issue of vitamin K2 subtypes. Vitamin K2 contains a chemical "tail" composed of repeating units called prenyl units. The most common forms of K2 contain either 4,5,7,8, or 9 prenyl units, and are therefore referred to as MK-4, MK-5, MK-7, MK-8, and MK-9. (The letter "M" in "MK" refers to "menaquinone"—the scientific name for the K2—and the "K" refers to the common name of vitamin K.) While human diets usually consist of about 10-25% K2, the proportion of these different K2 forms can vary widely. Fermented soy foods (mentioned earlier in this article as an important source of K2) tend to have greater amounts of MK-7. Cheese may have greater amounts of MK-8 and MK-9. However, in the average U.S. diet, MK-4 typically accounts for about one-third or more of all K2 due to its presence in eggs and meats.

How bone support works

The bone-related benefits of vitamin K appear to depend on at least two basic mechanisms. The first of these mechanisms involves a type of bone cell called osteoclasts. Osteoclasts are bone cells in charge of bone demineralization—they help take minerals out of the bone and make them available for other body functions. While the activity of these cells is important for proper health, we do not want too many osteoclasts (or too much activity by osteoclasts) since those imbalances would mean too much demineralization of bone. Vitamin K helps our body keep this process in check. The MK-4 form of vitamin K2 (also called menatetrenone) is known to block formation of too many osteoclasts, and perhaps also to initiate their programmed cell death (a process called apoptosis).

A second mechanism involves the role of vitamin K in a process called carboxylation. (This process is the same one discussed earlier in relationship to the stickiness of clotting factors required for proper blood clotting.) For our bones to be optimally healthy, one of the proteins found in bone—a protein called osteocalcin—needs to be chemically altered through the process of carboxylation. (Osteocalcin is not just any typical bone protein. It is a protein especially linked to our bone mineral density (BMD), and for this reason, it often measured in our blood when doctors are seeking to determine the health of our bone.) When too few of the osteocalcin proteins in our bone are carboxylated, our bones have increased risk for fracture. This unwanted risk appears to be particularly important with respect to hip fracture. Scientists refer to this bone problem as a problem involving "undercarboxylated osteocalcin" and they have determined that vitamin K can greatly improve the situation. Since vitamin K is required for proper activity of the carboxylase enzyme that allows carboxylation of the osteocalcin proteins in our bone, vitamin K can help restore these bone proteins to their proper place in our bone structure and strengthen the composition of the bone. In clinical studies, both K1 and K2 forms of vitamin K appear to play a role in osteocalcin carboxylation. Some studies show the K2 form (and specifically MK-4) to be especially helpful in postmenopausal bone protection.

Whether provided by the diet in the form of K1 or K2, this vitamin is becoming more and more focal in research on bone protection. Low levels of vitamin K intake are emerging as dietary risk factors for osteoporosis. Researchers have shown that increasing dietary vitamin K intake by 100 mcg per day—roughly doubling the average American adult intake for a time period of one full year—can lead to a significant increase in bone density in post-menopausal women. Low levels of vitamin K have also been associated with increased risk of arthritis. Low activity of vitamin K-dependent proteins inside the joints has been suggested as a likely mechanism for this increased risk.

Other Potential Health Benefits

Not suprisingly based on its role in photosynthesis and movement of electrons to generate energy, vitamin K may function as an important antioxidant nutrient especially in certain chemical forms (called "reduced" forms). In older men, vitamin K has been shown to help improve insulin resistance. In preliminary lab and animal studies, vitamin K has been investigated as a critical nutrient for protecting cells that line blood vessels, including both veins and arteries.

4. Copper

       Copper is a key mineral in many different body systems. It is central to building strong tissue, maintaining blood volume, and producing energy in your cells. Yet, for all its critical importance, you don't have much copper in your body—barely more than the amount found in a single penny. And those pennies in your pocket are only 2.5% copper by weight.

In the foods we commonly eat, there are only very small amounts of copper. As much as any dietary mineral, the amount of copper you eat is directly related to the amounts of minimally processed plant foods you get every day.

Of the World's Healthiest Foods, 12 are rated as excellent sources of copper, 37 are very good, and 42 are rated as good.

Role in Health Support

Antioxidant Protection

Copper is one of the co-factors for one form of an enzyme called superoxide dismutase (SOD). SOD is one of the major antioxidant enzymes in the body. As a measure of how important SOD is, amyotrophic lateral sclerosis—also known as Lou Gehrig's disease—is thought to be the result of an underfunctioning (SOD) enzyme.

From recent studies where young volunteers were fed a copper-depleted diet, reduced SOD function was an early result. In fact, these changes were apparent within the first month of the experimental diet.

In more advanced cases of copper deficiency, including people who have undergone gastric bypass surgery, this loss of antioxidant protection over a period of years can lead to irreversible damage to the nervous system. However, this does not appear to occur without the types of unusual deficiency risks detailed below.

Bone and Tissue Integrity

Copper is required to manufacture collagen, a major structural protein in the body. When copper deficiency becomes severe, tissue integrity—particularly bones and blood vessels—can begin to break down.

Luckily, it appears at the present time that a very severe and prolonged dietary deficiency of copper is necessary to lead to overt problems. For example, premature babies with immature gastrointestinal tracts can develop bone problems related to copper deficiency.

At least one recent author has speculated that the marginal copper status of the diets of about one-quarter of adults in the U.S. is related to eventual development of osteoporosis in some members of this group. For adults with borderline copper intake from food, deficient intake of nutrients like calcium and vitamin D is still likely to put them at greater risk than borderline intake of copper. Still, this low copper intake may be increasing their risk of osteoporosis and is very likely to be the subject of future research.

Energy Support

Copper plays two key roles in energy production. First, it helps with incorporation of iron into red blood cells, preventing anemia. Second, it is involved with generation of energy from carbohydrates inside of cells.

Each of these uses of copper also requires iron, and for this reason, the symptoms of copper deficiency can mimic those of low iron intake. 

Cholesterol Balance

Animal studies have demonstrated that copper-deficient diets lead to increases in blood cholesterol levels. In humans, this appears to be true in some situations, but not all. This should not be a surprise, as human diets are much more varied than those of laboratory animals. Interestingly, the effect of copper deficiency appears to be through increased activity of an enzyme called HMG-CoA reductase—the same enzyme targeted by the most commonly prescribed cholesterol medications.

5. Folate

     

            Many people are familiar with the name of this B complex vitamin, and it has long been recognized as a key nutrient in human health. Low intakes of folate can have devastating effects, ranging from birth defects to blood diseases and possibly even cancers.

Much more recent in our understanding of this critical B vitamin is its many different forms in food, and its influence far beyond birth defects, blood diseases, and cancers. In our Role in Health Support section, we will be giving you many more details on exciting new folate research.

If the word folate sounds like foliage to you, this is not an accident. The words share a common root (the Latin word folium, meaning "leaf"), which helps remind us that green plant foods can be among the richest sources of folate. However, as the chart and table in this article show, there are outstanding sources of folate in other food groups as well (especially legumes). .

Because of the promising role of folate in disease risk reduction, U.S. public health organizations have taken many steps to help increase intake of folate in the U.S. population. These public health programs have helped decrease the occurrence of neural tube defects associated with folate deficiency by as much as 30% over time. (Although enrichment of processed wheat flour with vitamins B1, B2, and B3 was practiced in the U.S. as early as the 1940's, it wasn't until 1998 that the U.S. Food and Drug Administration established guidelines for enrichment of processed wheat flour with folate.)

The adult Dietary Reference Intake (DRI) level for folate—and our WHFoods recommended daily intake level—is 400 micrograms DFE, where "DFE" stands for "Dietary Folate Equivalents." In the 2009-2010 National Health and Nutrition Examination Survey (NHANES), both male and female adults in the U.S. averaged well over this amount, with approximately 475 mcg DFE for adult women and 625 mcg DFE for adult men. However, a significant amount of this folate came in the form of fortified foods, enriched foods, or folate supplements rather than whole, natural foods. From a health standpoint, our WHFoods recommendations always focus on whole, natural foods, and if you regularly enjoy our recipes, you will be likely to do just as well as the average U.S. adult in your food-based intake of folate, without resorting to fortification or enrichment. Dozens of our recipes contain more than half of the recommended daily intake level for this B vitamin.

Our profiled foods include 10 excellent sources of folate, 17 very good sources, and 24 good sources. Included in these ranked sources of folate are foods from various food groups, including vegetables, fruits, and legumes. Given this wide variety of choices, we are confident about your ability to develop a whole foods meal plan that will provide you with plenty of folate.

Role in Health Support

As mentioned earlier, the past decade of folate research has taught us much more about the nature of this vitamin and its critical role in support of our health. However, we would also point out that, in general, folate has been a complicated vitamin for researchers to understand, and research on folate has produced some confusion when scientific findings need to get translated into practical steps that we can take in the grocery store and in the kitchen. Our goal in these next paragraphs is provide you with a framework for simplifying key aspects of recent research on this B vitamin.

Let's start off with the name of the vitamin itself. "Folate" is a very general name for a complicated family of nutrients found in both plant and animal foods. (At WHFoods, we use this very general term as our name for this B vitamin, and when we use it, we are not trying to specify any particular form of the vitamin. We just want to refer to this B vitamin in a consistent way.) To give you an idea of many different folate forms in food, consider the following list: methylfolates, dihydrofolates, monoglutamyl folates, and polyglutamyl folates. All of these vitamin forms can be found in varying amounts in whole, natural foods. By contrast, fortified and enriched foods are typically boosted in content with a single form of this vitamin, namely, folic acid. While you can find not only folic acid but many different forms of folate available in the form of dietary supplements, this vitamin gets added to food almost exclusively in the form of folic acid.

This complicated situation involving fortified foods led the National Academy of Sciences (NAS) to establish a new category for measuring dietary folate, called Dietary Folate Equivalents, or DFEs. If you consume 1 microgram of folate from a whole natural food, the NAS considers you to have consumed 1 microgram DFE. However, if you consume 1 microgram of folate from a food that has been fortified with folic acid, the NAS considers you to have consumed 1.6 micrograms DFE. Finally, if you take a folic acid supplement on an empty stomach in which no foods are simultaneously being consumed, the NAS considers you to have consumed 2 micrograms DFE. These differences in DFE calculation are based on studies measuring blood folate levels following intake of folate in various forms. The higher DFEs reflect higher blood levels associated with intake of supplemental folic acid versus natural food folate.

However, in order to more fully understand the health benefits of this vitamin, it would be a mistake to stop our discussion with consideration of supplemental folic acid, food folate, and DFEs. During the time that has passed since the NAS establishment of folate DFEs in 1998, there have been numerous advances in research on this vitamin. In comparison to the original DFE research, which showed about 50-60% bioavailability of food folate versus 85% bioavailability of supplemental folic acid, we now know that "bioavailable" can have many meanings and blood levels of folate are not always the best way to measure bioavailability. For example, we now know that polyglutamated folate found in vegetables and citrus fruits can be absorbed in the 60-98% range. We also know that a methylated form of folate (5-methyl-tetrahydrofolate) is the major form of folate in most plant cells, and that methylfolate appears to be the only form of this vitamin that crosses over the blood brain barrier and into the brain. This research has greatly increased interest in whole foods and the extent to which they naturally contain methylfolates.

Taken as a whole, these more recent research studies suggest that folate DFEs do not tell the whole story of this vitamin with respect to health benefits, and that whole, natural foods providing folate in a variety of forms are likely to be your best bet for obtaining health benefits related to this B vitamin. With this general guideline in mind, we would like to highlight specific areas in which folate health benefits have been most consistently documented in research studies.

Brain and Nervous System Health

Folate has long been known to help support production of nervous system function, and in particular, production of messaging molecules that are used by nerves to send signals throughout out body. More recently, however, research has broadened our understanding in this area of folate benefits.

In what has come to be named the BH₄ Cycle (where is an abbreviation for tetrahydrobiopterin), researchers have verified a close connection between production of multiple neurotransmitters (with special emphasis on serotonin and dopamine) and availability of folate. In fact, part of the molecule for which this BH₄ Cycle is named (dihydrobiopterin, or BH₂) can itself be readily converted into a form of folate (dihydrofolate). In addition, researchers now know that BH₄ cross over the blood brain barrier using the same transport mechanism as folate.

Interest in these nervous system messaging molecules and folate has been fascinating and widespread. Since much of the dopamine produced in our nerve cells begins with conversion of one amino acid (phenylalanine) into another amino acid (tyrosine), folate availability has been shown to be closely connected with this neurotransmitter pathway since BH₄ is required for conversion of phenylalanine into tyrosine. Yet broader still are possible connections between two additional neurotransmitters—glutamic acid and GABA—and folate metabolism.

Glutamine is the preeminent amino acid in our central nervous system, and it is the starting point for production of both glutamic acid and GABA. While glutamic acid is widely known as an "excitatory" neurotransmitter that can stimulate and speed up nerve cell activity, it actually plays a much wider role in nervous system health that includes proper brain development, differentiation of nerve cells, and survival of nerve cells. By contrast, GABA (gamma-aminobutyric acid) is widely regarded as a primary inhibitory neurotransmitter that can decrease nerve activity in certain areas and help initiate nervous system balance needed to pave the way for activities like sleep. Researchers do not yet know exactly how folate metabolism is related to metabolism of either glutamic aid or GABA. But what researchers do know is that folate is a B vitamin that contains a "tail" comprised of glutamic acid molecules. In fact, this glutamic acid vitamin "tail" controls absorption of folate from our intestines up into our body.

Overall Cardiovascular Support

During the past 10 years, research on the role of folate in nervous system support has greatly overlapped with folate research as it relates to support of the cardiovascular system. In fact, it might be hard to find an area of metabolic research that has generated more excitement that this overlapping area of folated-related events critical for health of our cardiovascular and nervous systems.

The overlap begins with the ability of adequate dietary folate to help keep blood levels of homocysteine in check. Homocysteine (Hcy) is a well-documented marker for cardiovascular disease that when excessive, represents a clearly increased risk for a variety of cardiovascular problems. (Hyperhomocysteinemia is the name of the condition for high Hcy in the blood.) Optimal levels of blood folate in one particular form (5-methyltetrahydrofolate, or 5-MTHF) can directly help lower Hcy levels. By helping to keep Hcy levels in check, healthy intake of folate can help lower risk of cardiovascular disease.

The benefits of folate for lowered cardiovascular risk do not stop with Hcy, however. Balanced levels of nitric oxide (NO) in the blood are equally well-established as being important for cardiovascular health. NO helps to regulate many cardiovascular functions, and appropriate levels of NO are considered protective again high blood pressure, excessive clumping of platelet cells, and other key aspects of blood flow.

Several different forms of an enzyme called nitric oxide synthase (NOS) are responsible for helping keep NO at appropriate levels in our blood. However, NOS enzymes cannot actually generate NO unless certain molecules are present to help the NOS enzymes function properly. One such molecule is BH₄ (tetrahydrobiopterin). Without enough BH₄ around, the NOS enzymes not only fail to produce enough NO, but they can actually worsen our cardiovascular health by producing too much of an oxygen free radical called superoxide. How is it that our bodies keep enough BH₄ around? Our bodies accomplish this task with the help of an enzyme called dihydrofolate reductase (DHFR). Of course, you can easily recognize the word "folate" in the name of this enzyme, because it is the same enzyme that converts folate into its most central bioactive form in the body, called tetrahydrofolate, or THF. In other words, the same enzyme that makes sure we have enough BH₄ around to keep up our nitric oxide levels also makes sure that we have the most centrally active form of folate. So you can see how our folate metabolism and our cardiovascular health are so closely connected on a metabolic level.

The key role of folate in our cardiovascular health does not stop here, however. It turns out that the overall cycle used by our body to regenerate active forms of folate—called the folate cycle—is directly tied to a central cycle in cardiovascular health called the methylation cycle. The methylation cycle is our primary way of understanding blood homocysteine levels, since this cycle continually interconverts the amino acid methionine (MET) and its fellow amino acid, homocysteine (Hcy). When our folate cycle breaks down, our methylation cycle breaks down. However, the way in which our methylation cycle breaks down is important because a breakdown in our folate cycle means a breakdown in our conversion of Hcy back into MET. In other words, a breakdown in our folate cycle means excessive accumulation of Hcy and increased risk of heart disease.

As complicated as these metabolic pathways might seem, the bottom line here is straightforward: folate is a central nutrient for cardiovascular health, and its role in cardio support is wide-ranging.

Specific Support of Red Blood Cell Production

It would be wrong to leave the topic of folate and cardiovascular health without making a special note about red blood cell production. Folate is one of many nutrients necessary for the production of red blood cells. These cells carry oxygen from the lungs to other parts of the body. Along with iron, copper, vitamin B12, and vitamin B6, a deficiency of folate can impair blood cell production.

Still, the deficiency of folate must be fairly severe to impair the production of red blood cells. Although this can occur, it is rare in the United States, where adults average more than the recommended daily intake level.

Reproductive Health

When women deficient in dietary folate become pregnant, the developing fetus is at increased risk for neural tube defects, a developmental condition that adversely affects nervous system development in the fetus. These neural tube defects are potentially devastating and can often cause loss of pregnancy.

Adverse effects on nervous system development in the fetus can occur very early in pregnancy, even before a woman is aware that she is pregnant. Because this very early occurrence of problems can be "invisible," it is important for women to consume enough of this nutrient before they become pregnant. From a practical standpoint, this scenario means special attention to folate intake by any woman who is considering pregnancy. As noted earlier, current evidence supports a conclusion that better folate intake by women prior to pregnancy can directly reduce risk of neural tube defects in a significant way.

Other Potential Health Benefits

Some studies show lower risk of breast cancer in women with higher dietary intakes of folate, as well as decreased cancer risk at other sites in both men and women. However, the overall research on folate and cancer risk is both controversial and on the surface, sometimes contradictory, since some studies find an association between high folate intake and increased cancer risk. However, this important area of research is often confounded by the failure of studies fail to distinguish between supplemental folic acid and natural food folate.

Prevention and treatment of mental health problems—especially depression—are topics of special interest in relationship to folate intake, and we have seen some preliminary studies linking folate deficiency to increased risk of depression.

6. Vitamin E

     Vitamin E is a blanket term for eight different naturally occurring nutrients—four different tocopherols and four different tocotrienols. Each of these vitamin E types is considered a fat-soluble antioxidant, and all eight are found in varying degrees in our daily diet. You may sometimes hear all eight molecules being referred to collectively as "tocochromanols."

The most famous of the vitamin E group is alpha-tocopherol. Both with respect to diet and high-dose supplementation, it is among the most intensely studied of nutrients. This is because its ability to help prevent free radical damage is well documented Public health recommendations for vitamin E are typically measured in milligram equivalents of alpha-tocopherol equivalents, or mg ATE. You will find this abbreviation being used throughout our live website charts.

However, despite the current prominence of alpha-tocopherol in public health recommendations and nutrition research, scientists are also interested in potential health benefits associated with lesser studied members of the vitamin E family, especially the tocotrienols. Like tocopherols (including alpha-tocopherol), tocotrienols are naturally occurring forms of vitamin E. Since they cannot be converted by humans into alpha-tocopherol, the tocotrienols are not considered relevant in meeting vitamin E needs. However, preliminary studies suggest that tocotrienols can provide us with health benefits in a way that is distinct from alpha-tocopherol, as well as other tocopherols. We look forward to future research in this area.

In this introductory description of vitamin E, it is also worth mentioning the unusually confusing nature of its units of measurement. There is really no such thing as "milligrams of vitamin E" since this description fails to explain what forms of the vitamin were considered when making the determination. As mentioned earlier, our website chart present vitamin E data in terms of "mg ATE" which stands for "milligrams of alpha-tocopherol equivalents." However, other types of equivalents can be used in presenting vitamin E data. For example, equivalents of d-alpha-tocopheryl acetate and equivalents of d-alpha-tocopheryl succinate can be used. (These two chelated, synthetic forms of vitamin E are frequently found in dietary supplements due to their longer shelf life).

While many of the World's Healthiest Foods are rich in vitamin E, we see that average U.S. adults fail to come close to a minimal requirement for this important nutrient. Below, we'll give you some guidance to help you chose foods rich in vitamin E that will better help you meet your daily needs.

You'll have a number of foods to choose from to build a menu that is rich in vitamin E. We list seven of the World's Healthiest Foods as excellent sources of vitamin E. Another six foods rate as very good sources, while twelve foods are listed as good.

Role in Health Support

Protection Against Free Radical Damage

Vitamin E is a potent antioxidant. Because it is fat soluble, we see it offer protection against damage to the fats that line the outside of every cell of our body.

When the fats in our membranes become damaged, important cell functions become compromised. Based on this important mechanism, researchers have studied whether diets low in vitamin E are associated with many diseases associated with aging.

We also see vitamin E protect fats from free radical damage before we eat them. We'll talk about the role of vitamin E in protecting foods during storage below in the Impact of Cooking, Storage, and Processing section.

Protection Against Heart Disease

Vitamin E helps protect LDL cholesterol (sometimes referred to as "bad" cholesterol) from free radical damage. Free radical damage typically involves an unwanted interaction with a reactive oxygen-containing molecule. When vitamin E is deficient—and under some other circumstances as well—it is possible for LDL cholesterol to become insufficiently protected and damaged by oxygen. When damaged in this way, the LDL cholesterol is often referred to as "oxidized LDL." If the process continues, it is possible for oxidized LDL to accumulate in blood vessel walls and create the early stages of hardening of the arteries (atherosclerosis).

Diets rich in vitamin E from vegetables, fish, and plant oils—like the Mediterranean diet for example—have been linked to cardiovascular prevention in large health surveys. Understand, though, that the potential benefits of this diet are not limited to or fully explained by vitamin E, and that dietary supplements of vitamin E (in comparison to vitamin E in food) have not demonstrated the same sort of preventive benefit that researchers hoped to see.

7. Potassium

     Potassium is a mineral found in varying amounts in almost all foods. Vegetables, especially green leafy varieties, are generally our richest sources of potassium.

We list three excellent sources of potassium, 16 as very good sources, and 39 as good sources by our Nutrient Rating System. In other words, over half of our WHFoods provide you with significant amounts of potassium! In fact, all of our WHFoods contain at least some small but measurable amount of this mineral.

Along with sodium, chloride, calcium, and magnesium, potassium is an electrolyte, meaning that it helps to conduct electrical charges in the body. Like all the other electrolytes, our bodies have evolved elaborate systems to control blood levels in a narrow range. This is good news since normal levels of potassium are absolutely critical to life—if potassium levels get too high or too low, the heart and nervous system completely shut down. Luckily, most of us are able to obtain enough potassium from foods to meet our most basic needs. But since just meeting a minimal intake need is not a recipe for health, many people in the United States often fail to obtain optimal amounts of this nutrient, and pay a health cost for it.

This is because Americans fail to regularly eat fresh fruits and vegetables, while eating heavily salted prepared foods. In fact, a recent survey suggests that only about 5% of Americans meet minimal goals for eating fruits and vegetables. If you do not regularly meet these goals, it will be difficult to ensure your potassium intake will be optimal.

It is impossible to understand the role of potassium without addressing sodium as well. Sodium and potassium exist in a partnership, and each important use of potassium requires sodium to maintain balance. Importantly, as average diets in the United States have become depleted in potassium, they have become much more concentated in sodium.

For example, a heavily salted commercial tomato juice—despite containing a potassium rich food like tomato—often contains a ratio of sodium to potassium of more than 2:1. This ratio is not a desirable one! By comparison, our Mushroom, Tomato, and Basil Frittata has a ratio of sodium to potassium of 1:3, a much more health-promoting pattern. In fact, we believe one of the central benefits of the World's Healthiest Foods approach is the way it rebalances sodium and potassium in a manner that is more consistent with good heart and kidney health.

Role in Health Support

Maintaining Normal Blood Pressure

Diets high in potassium are associated with improved blood pressure control. There are several mechanisms contributing to this beneficial effect, including improved kidney function, reduction in blood clotting, and more efficient opening of blood vessels. Because of these important benefits, therapeutic diets aimed at improving blood pressure control often place primary focus on increasing potassium from foods.

A good example of how foods rich in potassium can decrease elevated blood pressure is seen in the DASH (Dietary Approaches to Stop Hypertension) diet trials, where participants with high blood pressure who consumed an average of 8 to 10 total servings of fresh fruits and vegetables per day experienced significant drops in their blood pressure level. These servings focused on whole food choices similar to those featured in our recipes and the diet avoided processed and salt-choked choices like French fries. One key factor in these blood pressure benefits was the healthy balance of potassium to other minerals in these fresh fruits and vegetables.

Kidney Health

Perhaps the most important way to ensure strong kidney health is to keep your blood pressure under good control. As discussed above, diets high in potassium are well known to help with this.

In addition, diets rich in potassium have been associated with a reduction in kidney stone risk. This is thought to be because the naturally occurring potassium salts in plant foods help to neutralize acidity in the blood stream. This prevents leeching of calcium from the bones to buffer the acid, which in turn reduces urine calcium, preventing its deposition in the form of a stone. Please note that while diets rich in potassium can be helpful in preventing certain kidney-related problems in a healthy people with good kidney function, persons already known to have kidney problems and who are diagnosed with certain diseases of the kidney may need to carefully regulate their intake of potassium, since their kidneys might not otherwise be able to regulate the levels of potassium in their bloodstream.

8. Vitamin C

     Vitamin C may be the most familiar of all of the nutrients. Although most adults would be hard pressed to name a good food source of biotin or riboflavin, most everyone can name citrus fruits as good sources of vitamin C. It is also a commonly used nutritional supplement.

The first use of modern scientific methods to assess disease treatment was when the British navy used foods containing vitamin C (although the vitamin itself would remain undiscovered for nearly two centuries) to prevent scurvy among sailors. You could make a good case that this nutrition experiment is among the most important scientific findings in human history.

Despite the familiarity of the U.S. public with vitamin C and the popularity of vitamin C supplements, food intake of vitamin C by the average U.S. adult is not much higher than the Dietary Reference Intake (DRI) level. For men in the U.S. twenty years and older, this average is 96 milligrams per day, and for women in the U.S. twenty years and older, it is 82 milligrams per day. (The DRIs for these two groups are 90 milligrams and 75 milligrams, respectively.) So even though U.S. adults are averaging adequate intake of vitamin C intake from their food, the amount is not as high as some people might expect given widespread familiarity and interest in vitamin C.

Of the World's Healthiest Foods, a staggering 27 rate as excellent sources of vitamin C. Six of these contain a full day's requirement of vitamin C in a single serving. We also rate 14 very good and 14 good sources of the vitamin. This should give you plenty of variety with which to build a menu plan that easily exceeds your vitamin C goal.

Role in Health Support

Protection Against Excess Free Radicals

Vitamin C is probably best known as an antioxidant. This is a word that we use frequently but don't always stop to think about in terms of its meaning. Antioxidants are forms of molecules that help keep chemical reactions in our body in check. In particular, antioxidants help prevent excessive activity on the part of free radical molecules. (Free radicals are forms of molecules that tend to be very reactive, and too many free radicals in the wrong place at the wrong time can do damage to our cells and tissue.) Vitamin C and other antioxidants help prevent that damage. Damage to the lens of the eye, damage to molecules circulating around in our bloodstream, and damage to genetic material (DNA) in our cells are all examples of damage that have been shown to be prevented under certain circumstances by vitamin C.

One interesting application of vitamin C as an antioxidant is its ability to transform iron into a state that is better absorbed in the intestine. Including vitamin C-rich foods in recipes with your best iron sources can potentially be a way to enhance iron absorption.

Collagen

Vitamin C is required to produce collagen, a protein that plays a critical role in the structure of our bodies. Collagen is the framework for our skin and our bones, and without it, we would quite literally fall apart.

This is exactly what we see with severe vitamin C deficiency, or scurvy. People who have this condition lose teeth, bleed easily, and lose the strength of their bones. Luckily, it doesn't take much vitamin C to prevent this problem. As we've known for more than two centuries, a single lime per day would usually be enough. (However, as described earlier, we have dozens and dozens of great food choices that will give us as much vitamin C as a single lime!)

Brain Health

Vitamin C is necessary to make certain neurotransmitters. These neurotransmitters are the signals that carry thoughts, feelings, and commands around our brains and throughout our nervous system.

In particular, we need vitamin C to produce serotonin, a hormone that plays a critical role in wide variety of body systems, including the nervous system, endocrine system, immune system, and digestive system. Many of our moods, daily bodily rhythms (including sleep-wake cycles), and experiences of stress and pain have serotonin included as a factor in their occurrence. Some of the most commonly used prescription medications for depression (SSRIs, or Selective Serotonin Reupdate Inhibitors) also target this hormone. While we are not suggesting that dietary intake of vitamin C will automatically improve the quality of any experiences described above, we do recommend that you include vitamin C-rich foods on a daily basis as part of your overall well-being.

It is clear that Avocado is one of a kind fruit.