A multivitamin is a preparation intended to serve as a dietary supplement - with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in tablets, capsules, pastiles, powders, liquids, or injectable formulations. In addition to injection formulations, which are only available and administered under medical supervision, multivitamins are recognized by the Codex Alimentarius Commission (the UN authority on food standards) as the food category.
In healthy people, most scientific evidence suggests that multivitamin supplements do not prevent cancer, heart disease, or other diseases, and regular supplementation is not necessary. However, certain groups of people may benefit from multivitamin supplements, for example, people with malnutrition or those at high risk of macular degeneration.
There is no standard scientific definition for multivitamins. In the United States, a multivitamin/mineral supplement is defined as a supplement containing three or more vitamins and minerals excluding herbs, hormones, or medicines, in which each vitamin and mineral is inserted at a dose below the tolerable upper intake level as it is determined by the Food and Drug Administration, and does not pose any risk of adverse health effects.
Video Multivitamin
Products and components
Many formulas of multivitamins contain vitamin C, B1, B2, B3, B5, B6, B9, B12, biotin, A, E, D2 (or D3), K, potassium, iodine, selenium, borate, zinc, calcium, magnesium, manganese, molybdenum, betacarotene, and/or iron. Multivitamins are usually available in various formulas based on age and sex, or (such as prenatal vitamins) based on more specific nutritional requirements; multivitamins for men may contain less iron, whereas multivitamins for the elderly may contain extra vitamin D. Some formulas contain extra antioxidants. "High-efficacy formula" includes at least two-thirds of the nutrients called recommended dietary allowances.
Some nutrients, such as calcium and magnesium, are rarely included in 100% of the recommended benefits because the pill will become too large. Most multivitamins come in capsule form; tablets, powders, chews, liquids, and injectable formulations also exist. In the US, the FDA requires that any product that is marketed as a "multivitamin" to contain at least three vitamins and minerals; Furthermore, the dose should be below "tolerable upper limit", and multivitamins may not include herbs, hormones, or medications.
Maps Multivitamin
Usage
For certain people, especially the elderly, supplementing the diet with the addition of vitamins and minerals can have health effects; However, the majority will not benefit. People with dietary imbalances may include those on a strict diet and those who can not or will not eat nutritious food. Pregnant women and older adults have different nutritional needs than other adults, and multivitamins can be indicated by a doctor. Generally, medical advice is to avoid multivitamins, especially those containing vitamin A, during pregnancy unless they are recommended by a health care professional. However, the NHS recommends 10 g of Vitamin D per day during pregnancy and during lactation, as well as 400 Âμg of folic acid during the first trimester (first 12 weeks of pregnancy). Some people may need to take iron supplements, vitamin C, or calcium during pregnancy, but only on doctor's advice.
In the 1999-2000 National Health and Nutrition Examination Survey, 52% of adults in the United States reported consuming at least one diet supplement last month and 35% reported regular use of multivitamin-multimineral supplements. Women versus men, older adults compared to younger adults, non-Hispanic whites versus non-Hispanic blacks, and those with higher levels of education compared with lower levels of education (among other categories) tend to take multivitamins. Individuals who use dietary supplements (including multivitamins) generally report higher nutritional intake of foods and a healthier diet. In addition, adults with a history of prostate and breast cancer were more likely to use dietary supplements and multivitamins.
Precautions
The amount of each type of vitamin in a multivitamin formulation is generally adjusted to correlate with what is believed to produce optimal health effects in large population groups. However, the number of these standards may not correlate to what is optimal in certain subpopulations, such as in children, pregnant women and people with certain medical and medicinal conditions.
The health benefits of vitamins generally follow the biphasic dose-response curve, taking the shape of the bell curve, with the middle area being a safe intake range and the edges representing deficiency and toxicity. For example, the Food and Drug Administration recommends that adults with a 2,000 calorie diet get between 60 and 90 milligrams of vitamin C per day. This is the center of the bell curve. The upper limit is 2,000 milligrams per day for adults, considered to be potentially dangerous.
In particular, pregnant women should generally consult their physician before taking a multivitamin: for example, the excess or deficiency of vitamin A can cause birth defects.
Long-term use of beta-carotene, vitamin A, and vitamin E supplements can shorten age, and increase the risk of lung cancer in people who smoke (especially those who smoke more than 20 cigarettes per day), former smokers, exposed people asbestos, and those who use alcohol. [2] Many common brand supplements in the United States contain levels above the amount of DRI/RDA for some vitamins or minerals.
Severe vitamin and mineral deficiencies require medical care and can be very difficult to treat with a commonly sold free multivitamin. In such situations, special forms of vitamins or minerals with much higher potency are available, either as individual components or as special formulations.
Multivitamins in large quantities may pose an acute overdose risk due to the toxicity of some components, especially iron. However, in contrast to iron tablets, which can be lethal for children, the toxicity of a multivitamin overdose is very rare. There appears to be a small risk to complement users who experience acute side effects due to excessive micronutrient intake. There is also a strict limitation on the content of retinol for vitamin A during pregnancy that is specifically treated by prenatal formulas.
As stated in the Dietary Guidelines of the Harvard School of Public Health in 2008, multivitamins should not replace healthy eating, or keep up with unhealthy eating. In 2015, the US Prevention Services Task Force analyzed a study that included data for about 450,000 people. The analysis found no clear evidence that multivitamins prevent cancer or heart disease, help people live longer, or "make them healthier by any means."
Research
Provided that precautions are taken (such as adjusting the amount of vitamins for what is believed appropriate for children, pregnant women or people with certain medical conditions), multivitamin intakes are generally safe, but research is still going on with regard to what health effects multivitamins have.
The evidence of multivitamin health effects is largely derived from prospective cohort studies that evaluate the health differences between groups taking multivitamins and those not. The correlation between multivitamin and health intake found by the study may not be the result of multivitamins themselves, but may reflect the underlying characteristics of multivitamin takers. For example, it has been suggested that multivitamin takers may, overall, have more underlying disease (making multivitamins appear less useful in prospective cohort studies). On the other hand, it has also been suggested that multivitamin users may, on the whole, become more health-conscious (making multivitamins appear as more useful in prospective cohort studies). Randomized controlled studies have been encouraged to overcome this uncertainty.
Study cohorts
In February 2009, a study conducted in 161,808 postmenopausal women from the Women's Health Initiative study concluded that after eight years of follow-up "multivitamin use had little or no effect on general cancer risk, cardiovascular disease, or total mortality." Another 2010 study in the Journal of Clinical Oncology suggested that the use of multivitamins during chemotherapy for stage III colon cancer had no effect on treatment outcomes. A large prospective cohort study published in 2011, including more than 180,000 participants, found no significant association between multivitamin use and mortality from all causes. The study also found no impact of multivitamin use on the risk of cardiovascular disease or cancer.
A cohort study that received widespread media attention was the Physicians' Health Study II (PHS-II). PHS-II is a double-blind study of 14,641 US male doctors who were originally aged 50 years or older (average age 64.3) who lasted from 1997 to June 1, 2011. The average time that men followed was 11 years. The study compared total cancer (excluding non-melanoma skin cancer) for participants taking daily multivitamin (Centrum Silver by Pfizer) versus placebo. Compared with placebo, men who took a daily multivitamin had a small but statistically significant reduction in their total incidence of cancer. In absolute difference only 1.3 diagnoses of cancer per 1000 years of life. The hazard ratio for cancer diagnosis was 0.92 with a 95% confidence interval covering 0.86 to 0.998 (P = 0.04), showing a benefit of between 14% and 0.2% compared with placebo in the confidence interval. No statistically significant effects were found for any particular cancer or for cancer death. As indicated in the editorial in the same issue of the Journal of the American Medical Association, the researchers observed no difference in the effect of whether the study participant or non-adherence to multivitamin intervention, which reduced the dose-response relationship. The same editorial argues that this study does not properly address the problem of multiple comparisons, in which the authors neglect to fully analyze all 28 possible associations in the study - they argue that if this has been done the statistical significance of the results will be lost.
Using the same study of the same PHS-II study concluded that taking a daily multivitamin had no effect in reducing heart attacks and other major cardiovascular events, MI, stroke, and CVD mortality.
Systematic review and meta-analysis
A major meta-analysis published in 2011, including a cohort study and previous case control, concluded that multivitamin use was not significantly associated with breast cancer risk. It noted that one Swedish cohort study has shown such effects, but with all the studies taken together, the relationship was not statistically significant. A 2012 meta-analysis of ten randomized, placebo-controlled trials published in the Journal of Alzheimer's Disease found that daily multivitamins can improve the memory of direct memory, but did not affect the size of other cognitive functions.
Another meta-analysis, published in 2013, found that multivitamin-multimineral treatment "had no effect on mortality risk," and a systematic review of 2013 found that multivitamin supplementation did not increase mortality and may slightly lower it. A 2014 meta-analysis reports that there is "sufficient evidence to support the role of dietary multivitamin/mineral supplements to reduce the risk of age-related cataracts." A 2015 meta-analysis suggests that positive results on the effects of vitamins on cancer occurrences found in Physicians' Health Study II (discussed above) should not be ignored even if neutral results are found in other studies.
Expert agencies
A 2006 report by the US Healthcare Research and Quality Agency concluded that "regular supplementation with single nutrients or a mixture of nutrients for years has no significant benefits in the primary prevention of cancer, cardiovascular disease, cataracts, age-related macular degeneration or cognitive decline." However, the report notes that multivitamins have beneficial effects for certain sub-populations, such as people with malnutrition status that vitamin D and calcium can help prevent fractures in older people, and that zinc and antioxidants may help prevent age-related macular degeneration. in high-risk individuals.
A Cochrane Review on specific topics of age-related macular degeneration found that "taking vitamin E or beta-carotene supplements will not prevent or delay the onset of age-related macular degeneration."
According to the Harvard School of Public Health: "... a lot of people do not eat healthy food.That's why multivitamins can help fill the gap, and may have added health benefits." The US Diet Supplement Office, a branch of the National Institutes of Health, suggests that multivitamin supplements may be helpful for some people with certain health problems (eg, macular degeneration). However, the Office concludes that "most studies show that healthy people who take MVM [multivitamins] have no lower likelihood of disease, such as cancer, heart disease, or diabetes.Based on current research, it is impossible to recommend or against the use of MVM for stay healthy longer. "
Rule
United States
Due to their categorization as dietary supplements by the Food and Drug Administration (FDA), most of the multivitamins sold in the US do not need to undergo the usual pharmaceutical drug testing procedures.
However, some multivitamins contain very high doses of one or several vitamins or minerals, or are specifically intended to treat, cure, or prevent disease, and therefore require a prescription or drug license in the US. Since such drugs do not contain new substances, they do not require the same tests as those required by the New Drug Application, but are allowed in the market as a remedy for the Implementation Study Program on Drug Efficacy.
See also
- Food supplements
- Essential nutrients
- Food fortification
- megavitamin therapy
- Prenatal vitamins
References
News media reporting
External links
- Foods Supplement Fact Sheet: Multivitamin/mineral supplement, from U.S. National Institute of Health
- Multivitamin/Mineral Supplements, from the US Agency for Healthcare Quality and Quality.
- Multivitamins and cancer, from the American Cancer Society
- Safe top level for vitamins and minerals - Report of the UK Food Standards Expert Group on Vitamins and Minerals
Source of the article : Wikipedia
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