North Americans almost never suffer from vitamin deficiencies, except possibly for vitamin D, yet more than 50 percent of the population spends more than 30 billion dollars each year for vitamin pills and other nutritional supplements that they do not need. Forty-five percent of those who take vitamin pills believe that they will improve their health, but we have no good evidence that they do. The general consensus of the scientific community is that most people who take vitamin pills receive no benefit from them but are not harmed except for the money they have wasted.
Neither the American Heart Association nor the American College of Cardiology recommends vitamin or mineral pills to prevent heart attacks, and the US Preventive Services Task Force and the National Institutes of Health recommend against the routine use of vitamin or mineral pills to prevent chronic diseases. Many people say that they take vitamin pills because they may not be eating the right foods, but a lousy diet with vitamin pills is still a lousy diet.
A new analysis of 28 different studies that followed more than 83,000 healthy people over age 40 for up to 18 years found that pills containing B vitamins, beta carotene, vitamins C, vitamin D, vitamin E, zinc, copper or selenium (alone or in combinations) do not prevent or treat dementia and loss of brain function with aging (Cochrane Database of Systematic Reviews, December 17, 2018). Other studies that have failed to show benefits from vitamin or mineral pills include:
• A review of 179 different studies on vitamins A, B1 (thiamin), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), B9 (folic acid), C, D, E, beta-carotene, and the minerals calcium, iron, zinc, magnesium, and selenium, showed that there was no reduction in incidence of heart disease, stroke or premature death, compared to people who did not take vitamin pills (Journal of the American College of Cardiology, June 5, 2018;71(22):2570-2584).
• A review of 18 studies, following more than two million men and women for an average of 12 years, showed that vitamin and mineral pills do not reduce risk for dying from heart disease or strokes, or even for getting a stroke, regardless of age (Circulation: Cardiovascular Quality and Outcomes, July 2018;11(7)).
• A study followed almost 30,000 people in China, aged 40-69, 25 years after they had taken vitamin and mineral pills for five years. They had no reduction in death or cancer rates from vitamin or mineral pills (J National Cancer Institute, July 11, 2018).
• Additional studies are included in the References section below.
How Do Vitamins Affect Your Body? All of the vitamins necessary for human life and health come from foods, with the exception of vitamin D which comes primarily from sunlight. Most vitamins, particularly the B vitamins, are parts of enzymes that start chemical reactions. Chemical reactions break down food so that it can be absorbed into your bloodstream, start the processes that turn food into the fuel that your body uses for its various functions, and build and repair all of the tissues in your body. All of these chemical reactions are started by enzymes made by your body and by the bacteria that live in your body.
For example, for chemical A to go to chemical B and release energy for your cells to use, you need a first enzyme to start that chemical reaction. Then you need a second enzyme to break down chemical B to form chemical C and release more energy. If you have the first enzyme, you make lots of chemical B. If you lack the second enzyme that breaks down chemical B, chemical B could accumulate in large amounts in your body and may be toxic, which could cause disease and harm you.
How the B Vitamins Work Scientists do not know all of the chemical reactions started by vitamins, but they have worked out how some of the B vitamins help to make all of the proteins in your body. All human protein is made up of 21 building blocks called amino acids. Eight amino acids cannot be made by the human body, so they are called essential amino acids. The other 13 can be made from the essential amino acids, so you don't need to get them from your food; these are called the non-essential amino acids
For example, you use enzymes from the B vitamins to make the non-essential amino acid cysteine from the essential amino acid, methionine. However, methionine must go through several chemical reactions that make homocysteine before it makes cysteine. Thus Methionine > Homocysteine > Cysteine. However, homocysteine is associated with increased risk for heart attacks, so if it accumulates in the body it may be harmful. Vitamin B6 (pyridoxine) converts homocysteine to methionine and vitamin B9 (folic acid), and/or B12 (cobalamin) converts homocysteine to cysteine. Vitamin B3 (niacin) converts cysteine back into homocysteine. The B vitamins depend on all of the other B vitamins and more to avoid the buildup of toxic chemicals in your body.
Who May Benefit from Specific Vitamin or Mineral Pills Many years ago, scurvy was common in people who did not eat fruit as a source of vitamin C, and beriberi was common in people who lacked thiamine because they did not eat whole grains. Today diets are more varied and many processed foods are fortified, so these deficiency diseases are rarely seen, and then usually only in illness or severe deprivation. North Americans die far more often from diseases caused by excess food than from deficiencies.
Specific vitamins or minerals may be recommended for:
• people with vitamin deficiencies from inability to absorb certain vitamins such as B12
• people with conditions that make it difficult to absorb and retain food nutrients
• people with diseases that cause body or muscle wasting
• some people with heart disease
• pregnant women, who are given prenatal vitamins
• vegans who eat no animal products at all and need a source of vitamin B12
• some older people who do not eat properly or people with restricted eating patterns
• vitamin D for people who do not get adequate sunlight
• some people whose bodies cannot metabolize B12 (homotranscobalamine)
• possibly people with macular degeneration
• people with stomach problems who must take proton pump inhibitors
• possibly some people on metformin to treat diabetes
My Recommendations There is no scientific evidence that vitamin or mineral pills prevent dementia, heart attacks or chronic diseases in the general population. Micronutrients in food are typically better absorbed by the body than those from pills, so I do not recommend taking vitamin pills, mineral pills or other supplements unless you and your doctor have identified a special need such as those listed above. A lousy diet with supplements is still a lousy diet. Since nobody knows all the chemical reactions that go on in your body, I recommend that you follow what most scientists consider to be healthful lifestyle habits (including diet), and not depend on pills that have more questions than answers.
• eat lots of vegetables, fruits, and seeds (nuts, beans, whole grains)
• restrict sugar-added foods and drinks, red meat, processed meats and fried foods
• avoid overweight
• avoid all forms of tobacco
• restrict or avoid alcohol
• avoid recreational drugs and unnecessary prescription drugs
Data Associating Harmful Outcomes with Vitamin Pills
• A study of more than 35,000 men reported that high doses of Vitamin E pills are associated with increased risk for prostate cancer (JAMA. Oct 12, 2011;306(14):1549-56).
• A study of 38,772 older women shows that taking vitamin and mineral pills is associated with increased risk of death with iron pills have the strongest association (Arch Intern Med. 2011 Oct 10;171(18):1625-33).
• Women who take multivitamin supplements (vitamin C, E, beta-carotene, selenium, and zinc) are at increased risk for skin cancer (The Journal of Nutrition, Sept, 2007;137(9):2098-105).
• Vitamin A (beta-carotene) pills increase risk for lung cancer among smokers (Journal of the National Cancer Institute, Nov 6, 1996 Nov 6;88(21):1550-9) and The New England Journal of Medicine. April 14, 1994;330(15):1029-35.
• High doses of vitamin E increase risk of heart failure (JAMA. Mar 16, 2005;293(11):1338-47).
• High doses of vitamin E increase risk of heart failure (JAMA. Mar 16, 2005;293(11):1338-47).
• People who take daily vitamin pills do not live as long as those who do not take them (Lancet. Oct 2, 2004;364(9441):1219-28 and JAMA. Feb 28, 2007;297(8):842-57).
Data Associating Health Benefits with Vitamin Pills
• Taking vitamin pills for more than 20 years was associated with reduced risk for heart attacks (J Nutr. April, 2016).
• A 10-year follow-up study of 31,671 post-menopausal women with no history of heart disease showed that those taking vitamin pills had a slightly reduced risk for heart attacks (Am J Clin Nutr. Mar, 2011;93(3):674).
• Daily use of multivitamins was associated with decreased risk for cancer (JAMA. 2014 Aug 6;312(5):560 and Postgrad Med. Jan, 2015;127(1):107-16).
Data that Taking Vitamin Pills Offers No Health Benefits
• Researchers followed 86,142 women, aged 34–59, who had heart disease over many years. Those who took daily multivitamin pills did not have a reduced incidence of strokes or death from strokes (Eur J Neurol. Jul 30, 2017).
• A study followed for 5.4 years, 7540 men over age 60, given daily vitamin E, selenium, vitamin E and selenium, or placebo. The supplements offered no advantage whatever in preventing dementia (JAMA Neurol. May 1, 2017;74(5):567-573).
• Researchers gave 6000 men either one of four different supplements advertised to make you smarter or a placebo, and found that none of the supplements offered any advantage whatever over placebos in brain function ((Journal of the American Medical Association. May, 2017;317(20):2054).
• A review of 27 studies of 400,000 people showed that those who take vitamin pills daily do not live longer and did not suffer fewer attacks or cancers than those who do not take vitamin pills.
(Annals of Internal Medicine, April 17, 2017).
• Researchers followed 37,193 healthy women, older than 45 years, for an average of 16 years and found no advantage from taking daily vitamin pills in preventing heart attacks, strokes, heart surgical procedures, or death from heart attacks (Am J Clin Nutr. Jan, 2015;101(1):144-52).
• The Physicians' Health Study II showed that taking a daily multivitamin does not prevent death from heart attacks, strokes or heart disease after more than 10 years of follow up (JAMA. Nov 7, 2012;308(17):1751-60).
• Multivitamin pills did not prevent heart attacks, strokes, or death in women (Am J Clin Nutr. Jan, 2015;101(1):144-52).
*Neither vitamin E nor C pills reduced risk for heart attacks in 8 year follow up (JAMA. Nov 12, 2008;300(18):2123-33).
• A follow up study for more than 11 years of 28.517 middle-aged women showed that taking vitamin pills neither raised nor lowered high blood pressure (J Hypertens. Aug, 2016;34(8):1513-9).
• A 16-year prospective study of 37,193 women older than 45 and free of heart disease and cancer shows that taking multivitamin pills was not associated with, or caused, heart attacks, strokes, heart revascularization surgery or heart attack deaths (Am J Clin Nutr. Jan, 2015;101(1):144-52).
• An 8 year follow up study of 161 808 post-menopausal women shows that taking vitamin pills did not affect risk for common cancers, heart attacks or death rate (Arch Intern Med. Feb, 2009;169(3):294-304). Cancers specifically studied were of the breast, colon/rectum, endometrium, kidney, bladder, stomach, ovary, and lung.
• Researchers followed 161,808 women for 8 years and found that 41 percent took daily multivitamin pills. Those who took vitamin pills daily had the same incidence as those who took no vitamin pills of cancers of the breast, colon, rectum, endometrium, kidney, bladder, stomach, lung and ovary; heart attacks and strokes. Overall death rates were the same for both groups (Arch Intern Med. Feb 9, 2009;169(3):294-304).
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