Pyridoxin (Vitamin B6) and Disease Prevention

Six Principles of Physical, mental and Spiritual Health (PMSH)

Dr Shahid has summarized his six principles of health in a very simple form. Simplicity sometimes may not be politically correct. Well... What is wrong if you get the message and decide to live until 100 - 125 years and longer; without ever having to see any health care provider (MD,DO, DC, NP, PA, DP, DD, OD, psychiatrist, psychologist, spiritualist etc); during all your long and healthy life? Moreover, you will live a life that is full of vigor, enthusiasm, happiness and contentment for 100-125 years and even longer.

What else can anyone ask for? Does it sound too good to be true?

Well… IT IS "too good" and IT IS "true".

Remember! Health is what "YOU" make of it. It is "YOUR" responsibility. Not your health care provider's.

Follow these six principles of Dr Shahid’s Preventive Health. Also known as "Preventive Healthy Life Style (PHLS)", and see the result for yourself. You be the judge. The best part of it is, "it won’t cost you a penny". It is all free. And

"YOU WILL NEVER HAVE TO SEE ANY HEALTH CARE PROVIDER FOR AS LONG AS YOU LIVE."

As they say,

"One ounce of prevention is better than two pounds of cure."

So here are the six principles of holistic preventive healthy life style.

The basis of these six principles (holistic prevention) is already discussed in previous blogs. Let us discuss these principles in detail.


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The first principle of preventive health is a balanced diet. It consists of three parts:

1. Proteins, Fat & Carbohydrates in right proportion.
2. Vitamins, Minerals, fibers (VMF)
3. Water and Oxygen

We have completed an elaborate detail of the essential nutrients of balanced diet (Proteins, Fats and Carbohydrates) in previous blogs.

We have also given a brief description of #2 Vitamins, Minerals, fibers (VMF)

Let us describe vitamins in little more detail.

Very few people know what vitamins are and what is their real function in human body.

A brief history of vitamins was given in last blog. let us start with vitamins one by one in detail.

Vitamins are classified as either water-soluble or fat soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E and K) and 9 water-soluble (8 B vitamins and vitamin C).

A. Fat-soluble vitamins

Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Because they are more likely to accumulate in the body, they are more likely to lead to hypervitaminosis than are water-soluble vitamins. Fat-soluble vitamin regulation is of of particular significance in cystic fibrosis. Fat-soluble vitamins (vitamins A ,D, E and K), have been discussed already.

Now we discuss the Water-soluble vitamins.

B. Water-soluble vitamins

Water-soluble vitamins dissolve easily in water, and in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption. Because they are not readily stored, consistent daily intake is important. Many types of water-soluble vitamins are synthesized by bacteria.

The B vitamins are eight water-soluble vitamins that play important roles in cell metabolism. Historically, the B vitamins were once thought to be a single vitamin, referred to as vitamin B (much like how people refer to vitamin C or vitamin D). Later research showed that they are chemically distinct vitamins that often coexist in the same foods. Supplements containing all eight are generally referred to as a vitamin B complex. Individual B vitamin supplements are referred to by the specific name of each vitamin (e.g. B1, B2, B3 etc ).

We discussed a detailed account of Vitamin B1 (Thiamine) and Vitamin B2 (Riboflavinin), Vitamin B3 (Niacine), Vitamin B5 (Pantothenic acid) . Now we are discussing the next important water soluble vitamin Pyridoxine (Vitamin B6) . We discussed also the nature, sourses and medicinal use of Pyridoxin, Vitamin B6 deficiency, current issues and controversies about vitamin B6.


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Now we continue with the last part i.e. Disease Prevention and vitamin B6


Disease Prevention


1. Homocysteine and cardiovascular disease

2. Immune function

Low vitamin B6 intake and nutritional status have been associated with impaired immune function, especially in the elderly. Decreased production of immune system cells known as lymphocytes, as well as decreased production of an important immune system protein called interleukin-2, have been reported in vitamin B6 deficient individuals.

Restoration of vitamin B6 status has resulted in normalization of lymphocyte proliferation and interleukin-2 production, suggesting that adequate vitamin B6 intake is important for optimal immune system function in older individuals.

3. Cognitive function

A few studies have associated cognitive decline in the elderly or Alzheimer's disease with inadequate nutritional status of folic acid, vitamin B12, and vitamin B6 and thus, elevated levels of homocysteine. One observational study found that higher plasma vitamin B6 levels were associated with better performance on two measures of memory, but plasma vitamin B6 levels were unrelated to performance on 18 other cognitive tests. Similarly, a double-blind, placebo-controlled study in 38 healthy elderly men found that vitamin B6 supplementation improved memory but had no effect on mood or mental performance. Further, a placebo-controlled trial in 211 healthy younger, middle-aged, and older women found that vitamin B6 supplementation (75 mg/day) for five weeks improved memory performance in some age groups but had no effect on mood.

Recently, a systematic review of randomized trials concluded that there is inadequate evidence that supplementation with vitamin B6, vitamin B12, or folic acid improves cognition in those with normal or impaired cognitive function. Because of mixed findings, it is presently unclear whether supplementation with B vitamins might blunt cognitive decline in the elderly.

4. Kidney stones

A large prospective study examined the relationship between vitamin B6 intake and the occurrence of symptomatic kidney stones in women. A group of more than 85,000 women without a prior history of kidney stones were followed over 14 years and those who consumed 40 mg or more of vitamin B6 daily had only two thirds the risk of developing kidney stones compared with those who consumed 3 mg or less. However, in a group of more than 45,000 men followed over six years, no association was found between vitamin B6 intake and the occurrence of kidney stones. Limited data have shown that supplementation of vitamin B6 at levels higher than the tolerable upper intake level (100 mg/day) decreases elevated urinary oxalate levels, an important determinant of calcium oxalate kidney stone formation in some individuals. However, it is less clear that supplementation actually resulted in decreased formation of calcium oxalate kidney stones. Presently, the relationship between vitamin B6 intake and the risk of developing kidney stones requires further study before any recommendations can be made.

5. Disease Treatment
Vitamin B6 supplements at pharmacologic doses (i.e., doses much larger than those needed to prevent deficiency) have been used in an attempt to treat a wide variety of conditions, some of which are discussed below. In general, well designed, placebo- controlled studies have shown little evidence that large supplemental doses of vitamin B6 are beneficial.

6. Side effects of oral contraceptives

Because vitamin B6 is required for the metabolism of the amino acid tryptophan, the tryptophan load test (an assay of tryptophan metabolites after an oral dose of tryptophan) was used as a functional assessment of vitamin N6 status. Abnormal tryptophan load tests in women taking high-dose oral contraceptives in the 1960s and 1970s suggested that these women were vitamin B6 deficient. Abnormal results in the tryptophan load test led a number of clinicians to prescribe high doses (100-150 mg/day) of vitamin B6 to women in order to relieve depression and other side effects sometimes experienced with oral contraceptives. However, most other indices of vitamin B6 status were normal in women on high-dose oral contraceptives, and it is unlikely that the abnormality in tryptophan metabolism was due to vitamin B6 deficiency. A more recent placebo-controlled study in women on the lower dose oral contraceptives, which are commonly prescribed today, found that doses up to 150 mg/day of vitamin B6 (pyridoxine) had no benefit in preventing side effects, such as nausea, vomiting, dizziness, depression, and irritability.

7. Premenstrual syndrome (PMS)

The use of vitamin B6 to relieve the side effects of high-dose oral contraceptives led to the use of vitamin B6 in the treatment of premenstrual syndrome (PMS). PMS refers to a cluster of symptoms, including but not limited to fatigue, irritability, moodiness/depression, fluid retention, and breast tenderness, that begin sometime after ovulation (mid-cycle) and subside with the onset of menstruation (the monthly period). A review of 12 placebo-controlled double-blind trials on vitamin B6 use for PMS treatment concluded that evidence for a beneficial effect was weak . A more recent review of 25 studies suggested that supplemental vitamin B6, up to 100 mg/day, may be of value to treat PMS; however, only limited conclusions could be drawn because most of the studies were of poor quality.

8. Depression

Because a key enzyme in the synthesis of the neurotransmitters serotonin and norepinephrine is PLP-dependent, it has been suggested that vitamin B6 deficiency may lead to depression. However, clinical trials have not provided convincing evidence that vitamin B6 supplementation is an effective treatment for depression, though vitamin B6 may have therapeutic efficacy in premenopausal women.

9. Morning sickness (nausea and vomiting in pregnancy)

Vitamin B6 has been used since the 1940s to treat nausea during pregnancy. Vitamin B6 was included in the medication Bendectin, which was prescribed for the treatment of morning sickness and later withdrawn from the market due to unproven concerns that it increased the risk of birth defects. Vitamin B6 itself is considered safe during pregnancy and has been used in pregnant women without any evidence of fetal harm. The results of two double-blind, placebo-controlled trials that used 25 mg of pyridoxine every eight hours for three days or 10 mg of pyridoxine every eight hours for five days suggest that vitamin B6 may be beneficial in alleviating morning sickness. Each study found a slight but significant reduction in nausea or vomiting in pregnant women. A recent systematic review of placebo-controlled trials on nausea during early pregnancy found vitamin B6 to be somewhat effective. However, it should be noted that morning sickness also resolves without any treatment, making it difficult to perform well-controlled trials.

Food sources


Surveys in the U.S. have shown that dietary intake of vitamin B6 averages about 2 mg/day for men and 1.5 mg/day for women. A survey of elderly individuals found that men and women over 60 years old consumed about 1.2 mg/day and 1.0 mg/day, respectively; both intakes are lower than the current RDA.

Certain plant foods contain a unique form of vitamin B6 called pyridoxine glucoside; this form of vitamin B6 appears to be only about half as bioavailable as vitamin B6 from other food sources or supplements. Vitamin B6 in a mixed diet has been found to be approximately 75% bioavailable. In most cases, including foods in the diet that are rich in vitamin B6 should supply enough to prevent deficiency. However, those who follow a very restricted vegetarian diet might need to increase their vitamin B6 intake by eating foods fortified with vitamin B6 or by taking a supplement.

Supplements

Vitamin B6 is available as pyridoxine hydrochloride in multivitamin, vitamin B-complex, and vitamin B6 supplements.


Toxicity


Because adverse effects have only been documented from vitamin B6 supplements and never from food sources, safety concerning only the supplemental form of vitamin B6 (pyridoxine) is discussed. Although vitamin B6 is a water-soluble vitamin and is excreted in the urine, long-term supplementation with very high doses of pyridoxine may result in painful neurological symptoms known as sensory neuropathy.

Symptoms include pain and numbness of the extremities and in severe cases, difficulty walking. Sensory neuropathy typically develops at doses of pyridoxine in excess of 1,000 mg per day. However, there have been a few case reports of individuals who developed sensory neuropathies at doses of less than 500 mg daily over a period of months. Yet, none of the studies in which an objective neurological examination was performed reported evidence of sensory nerve damage at intakes below 200 mg pyridoxine daily. To prevent sensory neuropathy in virtually all individuals, the Food and Nutrition Board of the Institute of Medicine set the tolerable upper intake level (UL) for pyridoxine at 100 mg/day for adults. Because placebo-controlled studies have generally failed to show therapeutic benefits of high doses of pyridoxine, there is little reason to exceed the UL of 100 mg/day.


Drug interactions

Certain medications interfere with the metabolism of vitamin B6; therefore, some individuals may be vulnerable to a vitamin B6 deficiency if supplemental vitamin B6 is not taken. Anti-tuberculosis medications, including isoniazid and cycloserine, the metal chelator penicillamine, and antiparkinsonian drugs including L-dopa, all form complexes with vitamin B6 and thus create a functional deficiency. Additionally, the efficacy of other medications may be altered by high doses of vitamin B6. For instance, high doses of vitamin B6 have been found to decrease the efficacy of two anticonvulsants, phenobarbital and phenytoin, as well as L-dopa.


We shall continue next with the last of the vitamin B complex, folic acid.


For comment and questions please write to :

syedshahidmd@yahoo.com.au

P.S. I must thank all of those readers who send me comments and questions. I must tell them that their inspiring comments and questions are highly appreciated. Please continue to write, preferably via email.

Thanks

Sydshahid