Vitamin A

Overview

Vitamin A has essential actions in areas of health including:

helping cells reproduce normally — a process called “cellular differentiation.”
good vision — the first sign of a vitamin A deficiency is often poor sight at night.
proper development of an embryo and foetus.
keeping skin and mucous membranes that line the nose, sinuses, and mouth healthy
playing a role in immune system function, growth, bone formation, reproduction, and wound healing.

Beta-carotene is synthesised in humans to form vitamin A and vitamin A activity from high intakes of carotenes seems not to produce adverse levels of vitamin A. The safety of beta-carotene itself will be discussed separately from vitamin A.

Vitamin A is fat-soluble and readily accumulates in the liver. Therefore, if taken at high dosages on a daily basis, the vitamin can easily accumulate to dangerous levels in the liver and other tissues. However, in nutritionally deprived populations who do not have a steady, sufficient intake of vitamin A, the same high dosages may be necessary as occasional supplements in order to prevent the severe health consequences of vitamin A deficiency. This makes the safety of vitamin A highly dependent on both the daily level of intake and the duration of consumption.

Uses

Acne, Psoriasis, Eczema and other Skin disorders
Vitamin A can help clear up severe acne and psoriasis and have shown promise for treating other skin disorders, premature aging from the sun and warts.

Eye Disorders
Getting enough vitamin A in your diet is essential for good vision. Research shows that people who eat more foods with vitamin A are less likely to develop age-related macular degeneration. In addition, a large population study found that people who got high levels of vitamin A though their diets had a lower risk of developing cataracts. Vitamin A supplements may help slightly slow down the damage from retinitis pigmentosa, a hereditary disease that causes poor night vision.

Measles
For children who have vitamin A deficiency, supplements can reduce the severity and complications of measles. Children who are deficient in vitamin A are more likely to develop infections, including measles. In areas of the world where vitamin A deficiency is widespread or where at least 1% of those with measles die, the World Health Organization recommends giving vitamin A supplements to children who have measles. However, vitamin A does not seem to help unless a child has vitamin A deficiency. Never give a child high-dose vitamin A supplements without expert supervision.

Inflammatory Bowel Disease (IBD)
People with IBD, both ulcerative colitis and Crohn’s disease, may have a hard time absorbing all the nutrients their bodies need. Health care providers often recommend that people with IBD take a multivitamin, including vitamin A.

Cancer
Whether vitamin A can reduce the risk of cancer is not clear. People who eat a healthy diet with enough beta-carotene and other carotenoids from fruits and vegetables seem to have a lower risk of certain cancers, such as breast, colon, oesophageal, and cervical cancer. And some laboratory studies suggest that vitamin A and carotenoids may help fight certain types of cancer in test tubes.

One preliminary study suggests that a topical form of vitamin A may reduce abnormal growth of cells on the cervix, called cervical neoplasia.

Researchers are also investigating retinoids, a synthetic form of vitamin A, for skin cancer. People with certain types of skin cancer tend to have lower levels of vitamin A and beta-carotene in the blood.

Sources

Vitamin A, in the form of retinyl palmitate, is found in beef, calf, and chicken liver; eggs; fish liver oils; and dairy products, including whole milk, whole milk yoghurt, whole milk cottage cheese, butter, and cheese.

The body can also make vitamin A from beta-carotene and other carotenoids, fat-soluble nutrients found in fruits and vegetables that give them their colour. Most dark-green leafy vegetables and deep yellow/orange vegetables and fruits — sweet potatoes, carrots, pumpkin and other winter squashes, cantaloupe, apricots, peaches, and mangoes — contain substantial amounts of beta-carotene. By eating these beta-carotene rich foods, you can increase levels of vitamin A in your body.

Upper intake limits and risks

Regular intakes of excess vitamin A can lead to liver abnormalities (25,000 IU), bone fragility (27,000 IU) and birth defects (30,000 IU).

The Council for Responsible Nutrition considers supplements of 10,000 IU (3,000 µg) per day of preformed retinol to be safe for most people. As stated earlier, the recommendations for nutritionally replete populations must be considered separately from nutritionally deprived populations. In addition, even within nutritionally replete populations, intake from food sources can vary widely. Therefore, for people who consume high levels of vitamin-A-fortified foods or liver, a lower limit of 5,000 IU (1,500 µg) per day is recommended.

Vitamin D

Overview

Vitamin D is a fat-soluble vitamin that plays a role in many important body functions. It is best known for working with calcium in your body to help build and maintain strong bones. Vitamin D is also involved in regulating the immune system and cells, where it may help prevent cancer.

In children, a vitamin D deficiency can cause rickets, a condition of soft, weak bones. In adults, many people may not be getting enough vitamin D, especially those who work in offices and the elderly. People with dark skin do not absorb sunlight as easily as those with light skin, so their risk of low vitamin D is even higher. One study of childbearing women in the Northern U.S. found that 54% of African-American women and 42% of white women had low levels of vitamin D.

That’s important because researchers are beginning to find that low levels of vitamin D may be linked to other diseases, including breast and colon cancer, prostate cancer, high blood pressure, depression, and obesity. The evidence doesn’t prove that too little vitamin D causes these conditions, but that people with higher levels of vitamin D are less likely to get these diseases.

Uses

Getting the proper amount of vitamin D may help prevent several serious health conditions.

Osteoporosis
Vitamin D helps your body absorb and use calcium, which you need for strong bones. Getting enough vitamin D throughout your life is important, since most bone is formed when you are young. For post-menopausal women who are at higher risk of osteoporosis, taking vitamin D along with calcium supplements can reduce the rate of bone loss, help prevent osteoporosis, and may reduce the risk of fractures.

Other Bone Disorders
Vitamin D protects against rickets and osteomalacia, softening of the bones in adults. Seniors who do not get direct sunlight for at least 45 minutes per week should make sure they get enough vitamin D through food supplements.

Prevention of Falls
People who have low levels of vitamin D are at greater risk of falling, and studies have found that taking a vitamin D supplement (700 – 1000 IU daily) may reduce that risk. In seniors, vitamin D may reduce falls by 22%.

Parathyroid Problems
The four parathyroid glands are located in the neck. They make parathyroid hormone (PTH), which helps the body store and use calcium and phosphorus. Vitamin D is often used to treat disorders of the parathyroid gland.

High Blood Pressure (Hypertension)
In population studies, people with low levels of vitamin D seem to have a high risk of developing high blood pressure than those with higher levels of vitamin D. However, there’s no proof that low levels of vitamin D cause high blood pressure in healthy people.

Evidence about vitamin D and blood pressure has been mixed. When people with kidney disease or an overactive parathyroid gland (hyperparathyroidism) develop high blood pressure, low levels of vitamin D may play a role. But another large study found that taking vitamin D and calcium supplements did not lower blood pressure significantly or reduce the risk of developing high blood pressure in postmenopausal women. If you have high blood pressure, you should follow your optimal health guide’s advice about whether vitamin D might help.

Cancer
There is some evidence that getting enough vitamin D may lower your risk of certain cancers, especially of the colon, breast, prostate, skin, and pancreas. This evidence is based mostly on studies of large groups of people

Some research suggests that postmenopausal women who take calcium and vitamin D supplements may have a lower risk of developing cancer of any kind compared to those who don’t take these supplements.

Seasonal Affective Disorder (SAD)
SAD is a type of depression that happens during the long dark winter months. It is often treated with photo (light) therapy. A few studies suggest that the mood of people with SAD improves when they take vitamin D directly.

Diabetes
Population studies find that people who have lower levels of vitamin D are more likely to develop type 2 diabetes than people who have higher levels of vitamin D. But there is no evidence that taking vitamin D can help prevent or treat type 2 diabetes.

One study found that giving infants doses of 2,000 IU per day of vitamin D during the first year of life may help protect them from developing type 1 diabetes when they are older.

Heart Disease
Population studies suggest that people with low levels of vitamin D have a greater risk of developing heart disease, including heart attack, stroke, and heart failure compared to people with higher levels of vitamin D. Low levels of vitamin D may increase the risk of calcium build-up in the arteries. Calcium build-up is part of the plaque that forms in arteries when you have atherosclerosis and can lead to a heart attack or stroke. Other population studies show that people with lower levels of vitamin D are more likely to have risk factors for heart disease, including high blood pressure, type 2 diabetes, obesity, and high cholesterol.

Obesity
Population studies have found that people who have lower levels of vitamin D are more likely to be obese compared to people with higher levels of vitamin D. One high-quality study also found that postmenopausal women who took 400 IU vitamin D plus 1,000 mg calcium daily for 3 years were less likely to gain weight than those who took placebo, although the weight difference was small. Women who were not getting enough calcium to start with (less than 1,200 mg per day) saw the most benefit.

Overall Mortality
Population studies suggest that people with lower levels of vitamin D have a higher risk of dying from any cause.

Dietary and other natural sources

Vitamin D has been described as a sunshine-dependent vitamin. Some dietary vitamin D2 comes from plants, but the largest contribution to dietary intake of vitamin D is the vitamin D3 in fish liver oils, eggs, milk, and liver. Milk is commonly fortified with 10 µg (400 IU) of vitamin D3 per quart. Extremely high potency (40,000 to 50,000 IU) products—sold as prescription or sometimes over the counter—often consist of vitamin D2. Most vitamin D dietary supplements contain vitamin D3. The conversion of international units to metric weights is extremely simple for both vitamin D2 and D3: 1 µg equals 40 IU; 0.025 µg equals 1 IU.

Vitamin D3 (or D2) from foods, or vitamin supplements is inert and must undergo two hydroxylation reactions in the body for activation. The first occurs in the liver and the second in the kidneys, which converts the vitamin D into calcitrol As calcitriol, vitamin D is fundamentally involved in the formation of bone, and so its deficiency can lead to rickets in children or osteoporotic changes in adults.

Although the vitamin can be synthesised in the body with sufficient exposure to sunlight or another ultraviolet (UV) light source, most people are not exposed to such UV light in consistent and sufficient quantities. No extra vitamin D is required when skin exposure to UV light is ample; but without such exposure, a person is completely dependent on ingested vitamin D.

Although adequate UV light exposure can provide sufficient vitamin D, many elderly persons have limited sunlight exposure, inadequate dietary sources, and a decreased ability to activate vitamin D, making them susceptible to vitamin D deficiency (Gloth et al. 1995; Holick 1999). Elderly people are likely to have substantially increased needs for dietary vitamin D because of their decreased mobility and exposure to sun and decreased activation in the liver and kidneys.

Thus, the nutritional need for dietary vitamin D depends on the biosynthesis in the skin, which in turn is influenced by time of exposure to sunlight, season (sun intensity and clothing), latitude, skin pigmentation, and the use of sunscreens.

Safety Considerations and limits

The formation of vitamin D in the skin is slowed once dietary vitamin D intakes are sufficient and blood levels of the activated forms are high. Therefore, excess exposure to sunlight does not lead to vitamin D toxicity (Holick 1999; Hathcock et al. 2007).

Dietary vitamin D can, however, produce toxic effects when consumed in very large quantities, especially over an extended period of time. Studies have shown that subjects with abnormally high levels of vitamin D intake can suffer from a wide range of signs and symptoms, from dehydration to permanent mineral deposits in soft tissues, including muscle, heart, kidney, and cartilage. Continued intake of toxic levels can have severe and persistent adverse consequences.

The traditional—but not data-based—conservatism of vitamin D recommendations is rapidly being corrected to evidence-based assessments. These assessments indicate that larger amounts are now considered safe for most persons. The Council for Responsible Nutrition recommends upper limits for vitamin D supplementation of 250 µg (4,000 IU) per day.

Beta Carotene

Overview

Beta-carotene is one of many hundreds of food carotenoids. Beta-carotene is the most abundant form of provitamin A (material that can be converted into vitamin A) in fruits and vegetables. It gives yellow and orange fruits their rich colours. Beta carotene is an effective source of vitamin A in both conventional foods and vitamin supplements, and is generally safe.

Beta-carotene is an antioxidant. It protects the body from damaging molecules called free radicals. Free radicals damage cells through a process known as oxidation. Over time, this damage can lead to a number of chronic illnesses. There is good evidence that eating more antioxidants foods helps boost your immune system, protect against free radicals, and may lower your risk of heart disease and cancer.

Studies have shown that people with high intakes of beta-carotene or high blood levels of this nutrient have a reduced risk of various diseases, including cancer and heart disease (van Poppel and Goldbohm 1995). In addition, beta-carotene and some other carotenoids may play an important role in facilitating cell-to-cell communications (Acevedo and Bertran 1995). Because many carcinogens inhibit such cellular communications (Gregus and Klaasen 1996), protection of this activity by dietary substances could be an important function in the protection against cancer.

Dietary Sources

The richest sources of beta-carotene are yellow, orange, and green leafy fruits and vegetables (such as carrots, spinach, lettuce, tomatoes, sweet potatoes, broccoli, cantaloupe, and winter squash). In general, the more intense the colour of the fruit or vegetable, the more beta-carotene it has.

Beta-carotene is fat-soluble, so you should take it with meals containing at least 3 g of fat to ensure absorption.

Limits and safety levels

Extensive data show that beta-carotene supplements of 50 mg every other day (the equivalent to 25 mg per day) can be taken for more than a decade without harm in a large group of mostly nonsmokers (Hennekens et al. 1996). The Council for Responsible Nutrition concludes that an intake of 25 mg per day is acceptable for non-smokers. Skin discolouration may occur with larger amounts, but this effect is harmless and self-correcting with intake reduction.

The only evidence of adverse effects of beta-carotene comes from the ATBC and CARET studies, which involved long-term heavy smokers and asbestos workers. These data suggest a LOAEL of 20 mg per day for smokers or asbestos workers, but disparities between the ATBC and CARET results and other data prevent confident identification of any LOAEL for beta-carotene. Smokers and asbestos workers should first control these health risks, then evaluate whether beta-carotene supplements are necessary.

Sources

University of Maryland Medical Center

Pantothenic acid (Vitamin B5)

Vitamin B5, also called pantothenic acid, is one of 8 B vitamins. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly.

All B vitamins are water-soluble, meaning that the body does not store them and must be replenished daily.

In addition to playing a role in the breakdown of fats and carbohydrates for energy, vitamin B5 is critical to the manufacture of red blood cells, as well as sex and stress-related hormones produced in the adrenal glands atop the kidneys. Vitamin B5 is also important in maintaining a healthy digestive tract, and it helps the body use other vitamins, particularly B2 or riboflavin. It is sometimes called the “anti-stress” vitamin.

Your body needs pantothenic acid to synthesize cholesterol.

It is rare for anyone to be seriously deficient in vitamin B5. Symptoms of a vitamin B5 deficiency include fatigue, insomnia, depression, irritability, vomiting, stomach pains, burning feet, and upper respiratory infections.

High Cholesterol/High Triglycerides

Several small, double-blind studies suggest that pantethine may help reduce triglycerides, or fats, in the blood in people who have high cholesterol. In some of these studies, pantethine has also helped lower LDL (bad) cholesterol and raise HDL (good) cholesterol. In some open studies, pantethine seems to lower levels of cholesterol and triglycerides in people with diabetes.

Wound Healing

Studies, mostly in test tubes and animals but a few on people, suggest that vitamin B5 supplements may speed wound healing, especially following surgery. This may be particularly true if vitamin B5 is combined with vitamin C.

Rheumatoid Arthritis

Some early evidence suggests that pantothenic acid might help with symptoms of rheumatoid arthritis (RA). One study found that people with RA may have lower levels of B5 in their blood than healthy people, and the lowest levels were associated with the most severe symptoms. A small study conducted in 1980 concluded that 2,000 mg/day of calcium pantothenate improved symptoms of RA, including morning stiffness and pain.

Dietary Sources

Pantothenic acid gets its name from the Greek root pantos, meaning “everywhere,” because it is available in a wide variety of foods. A lot of vitamin B5 is lost when you food is processed, however. Fresh meats, vegetables, and whole unprocessed grains have more vitamin B5 than refined, canned, and frozen food. The best sources are brewer’s yeast, corn, cauliflower, kale, broccoli, tomatoes, avocado, legumes, lentils, egg yolks, beef (especially organ meats such as liver and kidney), turkey, duck, chicken, milk, split peas, peanuts, soybeans, sweet potatoes, sunflower seeds, whole-grain breads and cereals, lobster, wheat germ, and salmon.

Upper Limits

The Council for Responsible Nutrition recommends an upper limit of 1,000 mg / day for pantothenic acid, citing the lack of adverse effects with daily intakes as high as 10 g.

Source

University of Maryland Medical Center

Biotin (vitamin H)

Overview

Biotin is part of the B complex group of vitamins. All B vitamins help the body to convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly.

Your body needs biotin to metabolize carbohydrates, fats, and amino acids, the building blocks of protein. Biotin is often recommended for strengthening hair and nails and it is found in many cosmetic products for hair and skin.

Like all B vitamins, it is a water-soluble vitamin, meaning the body does not store it. However, bacteria in the intestine can make biotin. It is also available in small amounts a number of foods. Biotin is also important for normal embryonic growth, making it a critical nutrient during pregnancy.

As our bodies can produce it, serious deficiency of this vitamin is rare. Symptoms include hair loss, dry scaly skin, cracking in the corners of the mouth (called cheilitis), swollen and painful tongue that is magenta in color (glossitis), dry eyes, loss of appetite, fatigue, insomnia, and depression. People who have been on IV drip for a long period of time, those taking antiseizure medication or antibiotics long-term, and people with conditions like Crohn’s disease that make it hard to absorb nutrients are more likely to be deficient in biotin.

Cradle Cap (Seborrheic Dermatitis)

Infants who don’t have enough biotin often develop this scaly scalp condition.

Diabetes

Preliminary research indicates that a combination of biotin and chromium might improve blood sugar control in some people with type 2 diabetes, but biotin alone is inadequate.

Dietary Sources

Biotin can be found in brewer’s yeast; cooked eggs, especially egg yolk; sardines; nuts (almonds, peanuts, pecans, walnuts) and nut butters; soybeans; other legumes (beans, blackeye peas); whole grains; cauliflower; bananas; and mushrooms.

Raw egg whites contain a protein called Avidin that interferes with the body’s absorption of biotin. Long term consumption of raw egg whites is not recommended for this, and health, reasons.

Food-processing techniques can destroy biotin. Less-processed versions of the foods listed above contain more biotin.

Upper limits

The Council for Responsible Nutrition sets the upper limit as 2.5 mg / day although the US FDA has never given public notice of receipt of any reports of adverse effects associated with biotin.

Source

University of Maryland Medical Center
Council for Responsible Nutrition

Vitamin B12 (cobalamin)

Overview

Vitamin B12, also called cobalamin, is one of 8 B vitamins. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly. All B vitamins are water-soluble, meaning that the body does not store them and must be replenished every day.

Vitamin B12 is an especially important vitamin for maintaining healthy nerve cells, and it helps in the production of DNA and RNA, the body’s genetic material. Vitamin B12 also works closely with vitamin B9 (also called folate or folic acid) to help make red blood cells and to help iron work better in the body. Folate and B12 work together to produce S-adenosylmethionine (SAMe), a compound involved in immune function and mood.

Vitamins B12, B6, and B9 work together to control blood levels of the amino acid homocysteine. High levels of homocysteine are associated with heart disease.

Defficiency

Mild defficiency is relatively common with unwholesome diets and low stomach acid levels, which the body needs to absorb B12. Low levels of B12 can cause a range of symptoms including fatigue, shortness of breath, diarrhoea, nervousness, numbness, or tingling sensation in the fingers and toes. Severe deficiency of B12 causes nerve damage. Others at risk for B12 deficiency include:

Vegans, vegetarians who also don’t eat dairy or eggs – vitamin B12 is found only in animal products
People with problems absorbing nutrients, due to conditions such as Crohn’s disease, pancreatic disease, and people who have had weight loss surgery
People who are infected with Helicobacter pylori, an organism in the intestines that can cause ulcers. H. pylori damages stomach cells that make intrinsic factor, a substance the body needs to absorb B12
People with eating disorders
People with HIV
The elderly

Pernicious Anaemia

Pernicious anaemia is a type of anaemia that happens when stomach cells are not able to make intrinsic factor. Without intrinsic factor, your body cannot absorb vitamin B12. Symptoms include weakness, pale skin, diarrhoea, weight loss, fever, numbness or tingling sensation in the hands and feet, loss of balance, confusion, memory loss, and moodiness. Vitamin B12 supplements in high doses, either given as injections or orally, are prescribed to treat pernicious anaemia. Pernicious anaemia can be a dangerous condition and patients should always be co-treated with a doctor.

Heart Disease

Many studies suggest that people with high levels of the amino acid homocysteine are roughly 1.7 times more likely to develop coronary artery disease and 2.5 times more likely to have a stroke than those with normal levels. B complex vitamins, especially vitamins B9, B6, and B12, help lower homocysteine levels.

Age-Related Macular Degeneration

One large study found that women who took 1,000 mcg of vitamin B12 along with 2500 mcg of folic acid and 500 mg of vitamin B6 daily reduced their risk of developing AMD, an eye disease that can cause loss of vision.

Fatigue

Fatigue is one of the symptoms of a vitamin B12 deficiency. One small study, done several years ago, suggested that some people who were not deficient in B12 might gain more energy from B12 shots. Please consider other causes and solutions for fatigue to provide wholesome advice.

Breast Cancer

Although there is no evidence that vitamin B12 alone reduces the risk of breast cancer, population studies have shown that women who get more folate in their diet have lower risk of breast cancer. Vitamin B12 works with folate in the body, so it may help contribute to a lesser risk. Another preliminary study suggested that postmenopausal women who had the lowest amounts of B12 in their diet had an increased risk for breast cancer.

Male Infertility

Studies suggest that vitamin B12 supplements may improve sperm counts and sperm mobility.

Dietary Sources

Vitamin B12 is found only in animal foods. Good dietary sources include fish, shellfish, dairy products, organ meats — particularly liver and kidney– eggs, beef, and pork.

Upper Limits

The Council for Responsible Nutrition recommends an upper limit of 3,000 µg (3 mg) per day although it acknowledges that no toxic effects of B12 have been encountered in humans or animals at any level of oral intake (Miller and Hayes 1982; IOM 1998). The CNR states that the overall evidence indicates that vitamin B12 is virtually nontoxic. D

Source

University of Maryland Medical Center

Folic Acid / Folate (Vitamin B9)

Overview

Vitamin B9, also known as folate or folic acid, is one of 8 B vitamins. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly. Folic acid is the synthetic form of B9, found in supplements and fortified foods, while folate occurs naturally in foods. We will refer to both terms interchangeably below.

All the B vitamins are water-soluble, meaning that they must be taken each day as the body does not store them .

Folic acid is crucial for proper brain function and plays an important role in mental and emotional health. It aids in the production of DNA and RNA, the body’s genetic material, and is especially important when cells and tissues are growing rapidly, such as in infancy, adolescence, and pregnancy. Folic acid also works closely with vitamin B12 to help make red blood cells and help iron work properly in the body.

Vitamin B9 works with vitamins B6 and B12 and other nutrients to control blood levels of the amino acid homocysteine. High levels of homocysteine are associated with heart disease.

It is fairly common to have low levels of folic acid. Alcoholism, inflammatory bowel disease, and celiac disease can cause folic acid deficiency. Also, certain medications may lower levels of folic acid in the body. Folic acid deficiency can cause poor growth, tongue inflammation, gingivitis, loss of appetite, shortness of breath, diarrhea, irritability, forgetfulness, and mental sluggishness.

Pregnant women need more folic acid to lower the risk of neural tube birth defects, including cleft palate, spina bifida, and brain damage. Neural tube defects are birth defects caused by abnormal development of the neural tube, a structure that eventually gives rise to the brain and spinal cord. Since folic acid has been added to many grain foods in the U.S., such as bread and cereal, neural tube defects have decreased dramatically.

Birth Defects

As mentioned, pregnant women who don’t get enough folic acid are more likely to have children with birth defects. Pregnant women should get 600 mcg of folic acid per day. Women who plan to become pregnant should make sure to get the recommended 400 mcg per day, since many neural tube defects can happen shortly after conception, before a woman even knows she is pregnant.

Studies show that women who take folic acid supplements before conception and during the first trimester may reduce their risk of having children with neural tube defects by 72 – 100%. Folic acid may also help prevent miscarriage, although the evidence isn’t clear.

Heart Disease

Folate may help protect the heart through several methods. First, there is some evidence that getting enough folic acid in your diet can reduce your risk of heart disease, although this evidence is based on population studies and not more definitive clinical trials.

Also, many studies suggest that people with high levels of the amino acid homocysteine are roughly 1.7 times more likely to develop coronary artery disease and 2.5 times more likely to have a stroke than those with normal levels. B complex vitamins, especially vitamins B9, B6, and B12, help lower homocysteine levels.

Age-related Hearing Loss

One study suggests that folic acid supplements help slow the progression of age-related hearing loss in elderly people with high homocysteine levels and low folate in their diet. It isn’t known whether healthy seniors would benefit.

Age-Related Macular Degeneration

One large study found that women who took 2,500 mcg of folic acid along with 500 mg of vitamin B6 and 1,000 mcg of cyanocobalamin (vitamin B12) daily reduced their risk of developing AMD, an eye disease that can cause loss of vision.

Depression

There are myriad causes for depression but some studies show that 15 – 38% of people with depression have low folate levels in their bodies, and those with very low levels tend to be the most depressed. Supplementation of folate and other nutrients through food or food-based supplements may assist this condition.

Cancer

Folic acid in the diet seems to protect against the development of some forms of cancer, particularly cancer of the colon, as well as breast, cervical, pancreatic, and stomach. However, this evidence is based on population studies that show people who get enough folate in their diet have lower rates of these cancers. Researchers don’t know exactly how folate might help prevent cancer. Some think that folic acid keeps DNA healthy and prevents mutations that can lead to cancer. Low dietary intake of folate may increase the risk of developing breast cancer, particularly for women who drink alcohol. Regular use of alcohol — more than 1 ½ to 2 glasses per day — is associated with higher risk of breast cancer. One large study, involving over 50,000 women who were followed over time, suggests that adequate intake of folate may reduce the risk of breast cancer associated with alcohol.

Dietary Sources

Rich sources of folate include spinach, dark leafy greens, asparagus, turnip, beets, and mustard greens, Brussels sprouts, lima beans, soybeans, beef liver, brewer’s yeast, root vegetables, whole grains, wheat germ, bulgur wheat, kidney beans, white beans, lima beans, mung beans, salmon, orange juice, avocado, and milk.

Safety limits

The Council for Responsible Nutrition recommends an upper limit of 1,000 µg (1.25 mg) per day.

Sources

University of Maryland Medical Center
The Council for Responsible Nutrition

Vitamin B6 (Pyridoxine)

Overview

Vitamin B6 is a water-soluble vitamin that is important in carbohydrate, lipid, and amino acid metabolism. It is found in the body in three primary forms: pyridoxine (the common name given mainly to the alcohol form, or pyridoxol); pyridoxal (the aldehyde); and pyridoxamine (theamine).

Vitamin B6 helps the body make several neurotransmitters, chemicals that carry signals from one nerve cell to another. It is needed for normal brain development and function, and helps the body make the hormones serotonin and norepinephrine, which influence mood, and melatonin, which helps regulate the body clock.

Along with vitamins B12 and folic acid (B9), B6 helps control levels of homocysteine in the blood. Homocysteine is an amino acid that is associated with heart disease. Your body needs B6 in order to absorb vitamin B12 and to make red blood cells and cells of the immune system.

It is rare to have a significant deficiency of B6, although studies indicate many people may be mildly deficient, especially children and the elderly. Certain medications can also cause low levels of B6 in the body. Symptoms of mild deficiency include muscle weakness, nervousness, irritability, depression, difficulty concentrating, and short-term memory loss.

Dietary Sources

Good food sources of vitamin B6 include chicken, turkey, tuna, salmon, shrimp, beef liver, milk, cheese, lentils, beans, spinach, carrots, brown rice, bran, sunflower seeds, wheat germ, and whole-grain flour.

Upper Limits

The Council for Responsible Nutrition recommends a safe upper limit of 100 mg / day due to the complete absence of adverse effects in credible, well-designed studies at 100 and 150 mg levels and only marginal evidence of adverse effects at 200 mg (Parry and Bredenson 1985; Brush 1988).

Sources

University of Maryland Medical Center
Council for Responsible Nutrition

Vitamin B3 (Niacin)

Overview

Vitamin B3, also called niacin (nicotinic acid), is one of eight B vitamins. It has 2 other forms, niacinamide (nicotinamide) and inositol hexanicotinate, which have different effects from niacin. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly, and are needed for good brain function. All B vitamins are water-soluble, meaning that the body does not store them and must be replenished daily.

Niacin also helps the body make various sex and stress-related hormones in the adrenal glands and other parts of the body. Niacin helps improve circulation.

Symptoms of mild deficiency include indigestion, fatigue, canker sores, vomiting, and depression. Severe deficiency can cause a condition known as pellagra. Pellagra is characterized by cracked, scaly skin, dementia, and diarrhea. It is generally treated with a nutritionally balanced diet and niacin supplements. Niacin deficiency also causes burning in the mouth and a swollen, bright red tongue.

Dietary Sources

The best food sources of vitamin B3 are found in beets, brewer’s yeast, beef liver, beef kidney, fish, salmon, swordfish, tuna, sunflower seeds, and peanuts. In addition, foods that contain tryptophan, an amino acid the body coverts into niacin, include poultry, red meat, eggs, and dairy products.

Upper Limits

The Council for Responsible Nutrition recommends different upper limits depending on the form of vitamin B3 being taken.

Nicotinic Acid: 35 mg / day
Nicotinamide: 1,500 mg / day
Inositol Hexanicotinate: 4,000 mg / day

Sources

University of Maryland Medical Center
The Council for Responsible Nutrition

Vitamin B2 (Riboflavin)

Vitamin B2, also called riboflavin, is one of eight B vitamins. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly, and are needed for good brain function. All B vitamins are water-soluble, meaning that the body does not store them and must be replenished daily.

In addition to producing energy for the body, riboflavin also works as an antioxidant by fighting damaging particles in the body known as free radicals. Free radicals damage cells and DNA, and contribute to the ageing process, as well as the development of a number of health conditions, such as heart disease and cancer. Antioxidants such as riboflavin can fight free radicals and may reduce or help prevent some of the damage they cause.

Riboflavin is also needed to help the body change vitamin B6 and folate into forms it can use. It is also important for body growth and red blood cell production.

Acute deficiency in riboflavin is rare. However, elderly people and alcoholics may be at risk for riboflavin deficiency. Symptoms of riboflavin deficiency include fatigue; slowed growth; digestive problems; cracks and sores around the corners of the mouth; a swollen magenta-coloured tongue; eye fatigue; swelling and soreness of the throat; and sensitivity to light.

Cataracts

Vitamin B2, along with other nutrients, is important for normal vision. Some early evidence shows that riboflavin might help prevent cataracts, damage to the lens of the eye, which can lead to cloudy vision.

Migraine Headache

Several studies suggest that people who get migraines may reduce how often they get migraines and how long they last by taking riboflavin. One double-blind, placebo-controlled study showed that taking 400 mg of riboflavin a day cut the number of migraine attacks in half.

Dietary Sources

The best sources of riboflavin include brewer’s yeast, almonds, organ meats, whole grains, wheat germ, wild rice, mushrooms, soybeans, milk, yoghurt, eggs, broccoli, Brussels sprouts, and spinach.

Riboflavin is destroyed by light, so food should be stored away from light to protect its riboflavin content. While riboflavin is not destroyed by heat, it can be lost in water when foods are boiled or soaked. During cooking, roasting, and steaming preserves more riboflavin than frying or scalding.

Safety limits

The Council for Responsible Nutrition provides that the safe upper limit for vitamin B2 is 200 mg / day.

Sources

University of Maryland Medical Center