While the ideal way of obtaining vitamins is through eating a healthy diet, not all vitamins are equally absorbed by all people. As well, some conditions suggest that certain vitamin supplements should definitely be added to diets. For example, people with Irritable Bowel Syndrome (IBS) have difficulty absorbing vitamins from food, and may benefit from a good, and easily digestible multi-vitamin supplement.

What vitamins one takes needs to be tailored to the individual. A pregnant woman, for example, should start taking a pregnancy multi-vitamin that contains folic acid prior to conception. Taking folic acid significantly reduces the risk of certain birth defects when a daily amount is taken before the woman conceives.

Someone who is on a calorie-restricted diet may also need a good multi-vitamin because the person may not be getting enough vitamin amounts from their foods. Vegetarians particularly need vitamin B12, which is often lacking from the vegetarian diet. People who cannot consume milk products lose out on vitamin D, calcium, magnesium and potassium.

Most doctors also recommend that all women take a daily calcium supplement. This is especially true for women entering their 30s and older, since calcium can help forestall osteoporosis. Many also benefit from the vitamin A in fish oil and flaxseed oil, which has mood regulating benefits and may be helpful in preventing heart disease. Vitamin A levels should be carefully regulated, since too much vitamin A has been linked to birth defects. Those with heart rhythm irregularities should also not take fish oil, as it may actually increase the chance of having a dangerous arrhythmia.

People who are elderly, or young children who have very picky food habits may also benefit from taking vitamins that have a basic selection of various vitamins. Note that calcium and iron vitamins or minerals should never be taken together, since iron interferes with calcium absorption. People with immunodeficiencies should also take a multivitamin supplement.

Vitamins should not be a substitution for a healthy diet however, because it has been shown that vitamins in food tend to be much more easily absorbed. Further, food often contains beneficial ingredients that one can’t get from vitamins. Milk for example, contains calcium and vitamin D, as well as magnesium and potassium. Simply taking a vitamin D supplement will not completely compensate from what one misses by not consuming dairy.

Taking too many vitamins has also shown to be largely ineffective. Most extra vitamins, like extra vitamin C are simply excreted through urine and don’t provide much benefit. In fact, as important as it may be to take some vitamins, it is equally important not to take too many. The best bet is to get recommendations from a physician so that any suggested vitamins mesh well with one’s dietary needs, any medications one may take, and any medical conditions one has.