What You Should Know About Vitamin B6 Deficiency
B6, specifically, is a vitamin that plays a vital role in production of immune cells, hemoglobin as well synthesis of mood regulating hormones. Deficiency is rare, yet children, adults over 65, and women of reproductive age tend to be at risk. Symptoms include weak immune system, anemia, dermatitis, inflammation of the tongue, depression, and confusion.
Vitamins are organic compounds that are vital for our growth, immunity, and normal cell function. There are 13 essential vitamins that fuel our bodies to function optimally.1 Of the 13, vitamins like A and C frequently enjoy the spotlight. However, there are other vitamins that are just as essential for good health. Vitamin B6 is the perfect example.
Vitamin B6 Functions
As a member of the eight B complex vitamins, vitamin B6 is a water-soluble vitamin that is naturally present in many foods.2 Vitamin B6 plays a key role in the functioning of over 100 enzymes that catalyze chemical reactions in our bodies.
- Vitamin B6 is involved in the metabolism of proteins, fats, and carbohydrates and thereby unlocks energy from the food we eat.
- Vitamin B6 stimulates the synthesis of several neurotransmitters. These are chemicals that transmit signals between nerve cells. Serotonin (which affects our mood) and dopamine (which controls several important bodily functions) are two major neurotransmitters synthesized with help from B6.
- In partnership with vitamins B9 and B12, vitamin B6 regulates blood levels of the amino acid homocysteine. High levels of homocysteine are associated with heart disease, although the exact connection is still not very clear.
- Vitamin B6 helps our body absorb vitamin B12.
- Vitamin B6 is involved in the production of cells of the immune system. It promotes the production of lymphocytes and interleukin 2. Lymphocytes are white blood cells that decide how a body reacts to infectious microorganisms and other foreign invaders, while interleukin 2 is a protein that manages the activities of white blood cells.
- Vitamin B6 is also involved in the production of hemoglobin, which is found in red blood cells. Hemoglobin is responsible for their ability to carry oxygen throughout the body.3
Vitamin B6 Deficiency: What Can Happen
Low levels of vitamin B6 may be associated with the onset and progression of tumors, increasing the risk for cancer. Various observational studies have found a higher risk for colorectal, esophageal, and stomach cancers due to low vitamin B6 consumption.4
Vitamin B6 deficiency appears to be connected with cognitive decline and Alzheimer’s disease in the elderly. However, further studies are needed to confirm the link.5
Vitamin B6 deficiency is also found to impair the growth of white blood cells, especially in older individuals. In one study, healthy elderly people were subjected to depletion and repletion of vitamin B6. The depletion period saw a significant fall in the total number of lymphocytes and in the production of interleukin 2.6
Symptoms Of Vitamin B6 Deficiency
Some of the symptoms of extreme B6 deficiency are:
- Muscle weakness
- Mouth ulcers
- Inflammation of the tongue.
- Seizures in infants.
- Short-term memory loss.
- Worsening of PMS symptoms.7
Are You At Risk?
- Vitamin B6 deficiency by itself is rare. It usually happens along with a deficiency in other B complex vitamins, such as folic acid and B12.
- Common foods such as grains, poultry, eggs, meat, fish, potatoes, and milk are all rich sources of vitamin B6. So, if you’re eating a well-balanced diet, you don’t really have to worry about B6 deficiency.
- It is important to note that children, adults over 65, and women of the reproductive age are at an increased risk for B6 deficiency.
- Infants that are exclusively breastfed (up to 6 months) are also vulnerable to B6 deficiency, especially after 4 months. An infant’s B6 requirements are likely to be met only if the mother is adequately nourished throughout the 6 months.8
- People with kidney diseases, alcoholism, and autoimmune disorders are more prone to B6 deficiency. Examples of autoimmune disorders include rheumatoid arthritis, inflammatory bowel disease, celiac disease, Crohn’s disease, ulcerative colitis, and other malabsorption issues.9
- Certain medications prevent vitamin B6 metabolism, posing a risk for deficiency. In this case, supplements may be needed. Studies suggest that the estrogen in oral contraceptives interferes with B6 metabolism. Certain drugs that treat tuberculosis, Parkinson’s, asthma, and other respiratory diseases can all react with pyridoxine (an active form of B6) and make it unavailable. Long-term use of nonsteroidal anti-inflammatory drugs can also have the same effect. On the other hand, high doses of vitamin B6 can reduce the effectiveness of certain anticonvulsants.10
Make sure you discuss your ongoing medications with your doctor before taking any supplements.
How To Get Vitamin B6 From Food Sources
Luckily, many natural foods contain B6. So, eating a balanced diet should take care of your B6 requirements. It is important to remember that processed, frozen, or canned foods don’t have the same B6 content as fresh foods. But if you decide to boost your B6 intake from food sources, here is the good news: you cannot overdose! Because it is a water-soluble vitamin, your body can eliminate the excess through urine.11
Best Vitamin B6 Sources
Some of the best sources of vitamin B6 include:
- Fish such as tuna, salmon, and cod
- Organ meat (such as liver) and meat (such as chicken and turkey)
- Starchy vegetables such as squash and potatoes
- Non-citrus fruits such as banana and avocado
- Dairy products such as skimmed milk and cheese
- Dry fruits such as dates, raisins, walnuts, and hazelnuts
- Vegetables such as Brussels sprouts, cooked spinach, and cabbage.
Other rich sources are peanut butter, wheat bran, fortified breakfast cereals, soybeans, and yeast.12
Vegetarians, Take Heed
Individuals who follow a very strict vegetarian diet may not get as much B6 out of vegetarian sources as non-vegetarians do. This is because plant foods commonly contain pyridoxine glucoside, a unique form of vitamin B6. It is only about 50 percent available to the body compared to B6 sourced from other foods or supplements. Experts even say that vegetarians may need to opt for a supplement or eat foods that are fortified with vitamin B6.13
How Much Is Enough?
The Recommended Dietary Allowance (RDA) for vitamin B6 is less than 2 mg per day, but the exact amount varies with gender and age. Pregnant or lactating women and older adults may require higher amounts.14 The National Health and Nutrition Survey (2003–2004) of over 6,000 participants above age 1 notes that this RDA values may not be enough for certain groups like smokers, blacks, and women who use or have used oral contraceptives. About 3 to 4.9 mg per day appeared to be adequate for such groups.15 Further studies will help firm this up, though. Until then, your doctor is the best judge of whether you need supplements and, if so, how much.
Vitamin B6 Toxicity
B6 toxicity is a rare condition that can happen when you take too many supplements for too long. Vitamin B6 toxicity can cause peripheral neuropathy, a condition characterized by the loss of sensations in the arms and legs. In very severe cases, it can affect walking, too. It is a reversible condition that recedes once vitamin B6 consumption is corrected.16 To avert such a condition, the Food and Nutrition Board of the Institute of Medicine have set 100 mg per day of pyridoxine as the tolerable upper intake level for adults.17
References [ + ]
|1.||↑||Vitamins. U.S. National Library of Medicine.|
|2, 9.||↑||Vitamin B6. National Institutes of Health.|
|3, 7.||↑||Vitamin B6 (Pyridoxine). University of Maryland Medical Center.|
|4, 10, 13, 17.||↑||Vitamin B6. Oregon State University.|
|5.||↑||Selhub, Jacob, Laura C. Bagley, Joshua Miller, and Irwin H. Rosenberg. “B vitamins, homocysteine, and neurocognitive function in the elderly.” The American journal of clinical nutrition 71, no. 2 (2000): 614s-620s.|
|6.||↑||Meydani, Simm Nikbin, Judy D. Ribaya-Mercado, Robert M. Russell, Nadine Sahyoun, Frank D. Morrow, and Stanley N. Gershoff. “Vitamin B-6 deficiency impairs interleukin 2 production and lymphocyte proliferation in elderly adults.” The American journal of clinical nutrition 53, no. 5 (1991): 1275-1280.|
|8.||↑||Nutrient Adequacy of Exclusive Breastfeeding For The Term Infant During The First Six Months of Life. World Health Organization.|
|11.||↑||Vitamins and Coenzymes. Rose-Hulman Institute of Technology.|
|12.||↑||Water-Soluble Vitamins – 19: Vitamin B6. Asia Pacific Journal of Clinical Nutrition.|
|14.||↑||Vitamin B6. U.S. National Library of Medicine.|
|15.||↑||Morris, Martha Savaria, Mary Frances Picciano, Paul F. Jacques, and Jacob Selhub. “Plasma pyridoxal 5′-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003–2004.” The American Journal of Clinical Nutrition 87, no. 5 (2008): 1446-1454.|
|16.||↑||Vitamins and minerals – B vitamins and folic acid. National Health Services.|