Supplements are no substitute for a balanced diet
The most important thing to remember is that supplements are no substitute for a balanced diet. Even the best vitamin studies only show a partial reduction in the risk of disease. No supplement allows a person to smoke, drink a lot of alcohol, eat whatever they want and still stay healthy. There are many substances, other than vitamins and minerals, which play an essential role in protecting against disease and improving health. Many studies show that people whose diets are high in fruit and vegetables live longer. For example, eating broccoli, carrots and leafy green vegetables does appear to be more protective than taking beta carotene and vitamin C supplements. As well as being a good source of beta carotene and vitamin C, broccoli contains compounds known as indoles that may protect against certain forms of cancer. It is also high in fiber.
When should you take supplements?
Vitamins work with food so supplements should usually be taken with meals. This also helps to minimize the nausea, heartburn and other gastric disturbances that some supplements can cause if taken on an empty stomach. The digestive juices can help to break down supplements so they are better absorbed. Supplements can be easier to swallow if taken with thicker liquids such as juices. It may be better to take supplements in smaller doses several times per day.
Some experts feel that, if vitamins are taken once a day it should be after the largest meal, which is usually dinner. Others feel that the body is in the best state to absorb nutrients earlier in the day.
Some vitamins and minerals compete for absorption or antagonize each other. In these cases, it may be best to take the supplements at different times; although if a person is taking large doses of supplements, these interactions may not matter.
Can large doses of vitamins be harmful?
For the majority of people who take a daily multivitamin supplement with no more than 100 per cent of the RDA, the risks of side effects are probably small. However, high doses of some vitamins can have serious side effects.
Fat soluble vitamins stay in the body longer than water soluble ones, and there have been cases where large doses of vitamin A and vitamin D have had toxic effects. These cases are rare and symptoms disappear when the large doses are stopped. Research has suggested that temporary and even permanent damage can be caused by overdosing on B vitamins. People at risk of developing kidney stones should avoid large doses of vitamin C.
Interactions between different nutrients are very complex. Minerals work in critical ratios to one another. Too high an intake of one mineral may result in a deficiency of another so minerals should be taken in one-to-one RDA ratios. For example, excessive zinc intakes can result in iron and copper losses, so if daily zinc intake is doubled from 15 mg to 30 mg, then daily iron intake should be doubled from 10 mg to 20 mg to maintain the ratio.
Are large doses of vitamins beneficial for certain conditions?
Megavitamin or megadose therapy is the use of vitamins and minerals in amounts greater than ten times the RDA. Vitamins exert their natural physiological functions by binding to compounds such as enzymes. The amount of a particular enzyme that a cell can make is limited, and when the vitamin has bound to all the available enzymes, it may not exert any greater physiological effect. Vitamins and minerals in doses larger than those needed for these effects exert pharmacological or drug-like effects. An example of this is the use of niacin at 40 times the RDA to lower cholesterol.
The use of vitamins and minerals in this way is relatively new and in most cases, extremely controversial. Many of these treatments are not accepted by mainstream medical doctors for the reason that there is a lot of ambiguity, incomplete information and hypothesis.
Orthomolecular medicine is defined as “the preservation of good health and the treatment of disease by varying the concentrations of substances in the human body that are normally present and required for health.” This definition was given by the Nobel Prize winning chemist, Linus Pauling, who believed that many diseases can be treated or prevented by finding the optimal amounts of nutrients required for each person’s health.
Orthomolecular medicine is concerned not only with maintaining optimal health but with the prevention and treatment of disease. Experiments using large doses of vitamins have included niacin therapy for schizophrenia, vitamin C for cancer and viral illnesses, and vitamin B6 for carpal tunnel syndrome. The results of these and other nutrition studies have generated a lot of media attention. One of the main criticisms of those who use orthomolecular medicine is that their research has little support from clinical trials.