Vitamin B6 is a very hard-working vitamin that is probably best known for its ability to balance hormonal changes in women. In addition, it is probably the most important of the B-vitamins for the immune system, enabling the body to protect itself from infection and, possibly, to inhibit the growth of cancer cells. It aids the production of new cells, including those that make up the immune system and the red blood cells.
Likc so many of the B-vitamins, vitamin B6 enables the body to process dietary protein, fat, sugars and starches effectively, and may help in weight control. It helps to control mood and behaviour, and is one of the vitamins that nutritionists recommend for children who are hyperactive or have learning difficulties. Vitamin B6 is also needed to keep skin healthy and it may help to prevent conditions such as dandruff, eczema and psoriasis.
Availability in Food
Vitamin B6 is readily absorbed into the body, but vitamin B2 and magnesium are both needed to convert it into its active form. Fortunately, these are both found in many of the same foods that contain vitamin B6, such as liver, kidney, sunflower seeds, wheat germ, walnuts, beans and eggs (see also p26). The production of the active form of vitamin B6 is also aided by exercise.
Although vitamin B6 is present in many foods, it can be destroyed by sunlight, so foods that contain it should be stored in the dark. It is lost during cooking and when foods are processed, for example during milling. The bacteria in the intestine can supplement the diet by manufacturing extra supplies. Vitamin B6 is not stored in the body, and foods containing it should be eaten several times a day as it is rapidly lost in the urine.
What if your intake is too low?
As vitamin B6 has such a wide range of activity, the whole body is involved if deficiency occurs and many of the symptoms are similar to those seen when vitamins B2 and B3 are lacking. Indeed, vitamin B6 is essential for the body to make its own vitamin B3.
In addition to the symptoms specific to women, vitamin B6 deficiency can cause irritability, nervousness, insomnia, weakness and even convulsions. Skin changes include dermatitis and acne. The nails may be ridged and the tongue inflamed. Asthma and other allergies may develop, as may anaemia. Bone changes include osteoporosis and arthritis, and kidney stones can occur.
When extra may be needed
- When taking the birth-control pill or receiving hormone replacement therapy
- If you suffer from pre-menstrual symptoms
- During pregnancy and when breast feeding • If you suffer from psychological problems, such as depression or anxiety
- When on a calorie-restricted diet for any reason (this includes slimmers and older people with small appetites)
- If you consume moderate or large amounts of alcohol
- If you eat a high-protein diet, or a diet high in sugar and processed foods
- If you are allergic to monosodium glutamate or tartrazine
(Pregnant and breast:feeding women should consult a doctor, midwife, or qualified nutritional therapist bifore taking any vitamin or mineral supplements.)
Can too much be toxic?
Supplements should not exceed 50mg per day unless prescribed by a doctor. You may have vivid dreams if you take supplements in the late evening.
Extreme supplementation (over 2,OOOmg a day) could cause neurological damage. If you are takir levo-dopa, which is prescribed for Parkinson's disease, you should not take vitamin B6 supplements as they can inactivate it. (This does not occur with 'Sinemet'.)
Using a supplement
If you wish to take a supplement, vitamin B6 is best taken as part of a balanced B-vitamin tablet capsule, unless your doctor or nutritional health practitioner advises otherwise. ldeally, vitamin B6 supplements should be divided into more than one dose because any excess is rapidly lost in the urine.
Vitamin B6 and Women
Vitamin B6 has a particular importance for women, as it seems able to reduce the symptoms that are caused when hormone levels change. Unfortunately, many women do not eat enough foods that are rich in vitamin B6, and are prone to a variety of symptoms at different stages of life, such as:
- Pre-menstrual fluid retention causing breast tenderness and emotional symptoms
- Pre-menstrual acne
- Period pains
- Nausea and sickness in early pregnancy
(Note: although many women do take moderate doses if vitamin B6 supplements during the first three months of pregnancy, its absolute safety has not been established, and individual advice should be sought.)
- High blood pressure, fluid retention and poor control of blood sugar in later pregnancy
- Emotional symptoms (mood swings, depression and loss of sex drive) when taking the birthcontrol pill or hormone replacement therapy.
In the short term, taking vitamin B6 supplements will often help to alleviate these symptoms. However, it is also important to improve your diet because the B-vitamins occur in the same foods, and deficiency in one of the B-vitamins often means that others will be in short supply as well.
Keep your heart healthy
There is growing evidence that vitamin B6 and folic acid can work together to reduce the risk of heart attacks. They enable the body to break down excessive levels of homocysteine, a substance that is known to predispose to heart attacks. Good sources of both vitamins are brewer's yeast, green leafy vegetables and foods made from whole wheat or oats. In addition, a number of breakfast cereals are now fortified with these vitamins.