Are vitamin supplements worth it?
Vitamins are essential for our bodies to function properly. We only need them in very small amounts, and since we are unable to make these important molecules ourselves, we need to get them from other sources (mostly from our diet).
With this in mind, it makes sense to take a multivitamin supplement to keep ourselves in the best possible health, right? Unfortunately, it’s not that simple. In fact, taking some supplements may even do more harm than good.
What are vitamins?
There are thirteen different vitamins that we need: vitamins A, C, D, E and K, and the eight different B vitamins. Without the right amounts of each key vitamin, we risk developing diseases such as scurvy, rickets, night blindness or anaemia, to name a few.
Vitamins A, D, E and K are fat-soluble, meaning they dissolve in fats and oils. Once we absorb these vitamins from the foods we’ve eaten, they are then stored away in our fatty tissues for later. The water-soluble vitamins (vitamin C and all the B vitamins) tend to be flushed out of our bodies fairly easily, so we need to consume them regularly in consistent amounts over time.
In addition to vitamins, there are other essential nutrients we need that are not made (synthesised) by our bodies—the essential fatty acids and amino acids—that we also get from the food we eat.
The idea of being able to obtain all the essential nutrients we need in a single tablet or magic powder is appealing, particularly if we feel our diets might not be entirely up to scratch. However, several studies and scientific reviews have consistently shown that, for most people, it is better for our health to obtain all our nutrients from our food supply.
Vitamin supplements typically contain only one ‘active ingredient’ in isolation, whereas food brings a whole range of different nutrients together in different combinations. It’s thought that this has an impact in terms of how well we can absorb and use those nutrients—the fat-soluble vitamins, for instance, need to be carried along by the fats and oils of the foods we eat.
What does the evidence say?
A recent review of many studies investigating the effects of taking vitamin supplements found that, for most common vitamin supplements, there was no evidence that they had beneficial effects for preventing heart disease, stroke or premature death. This echoes earlier studies that found no evidence vitamin supplements were any good at preventing cardiovascular disease or cancer, and that, in some cases, certain supplements might even increase your risk of an early death.
The way our bodies store, use and get rid of excess vitamins also has an impact on whether getting too much of any one vitamin is likely to cause problems. Fat-soluble vitamins are easy for our bodies to store away, but they can’t be flushed out as easily as the water-soluble vitamins can, so they can become toxic in large accumulated amounts. For example, too much of fat-soluble vitamin A can cause vision changes, bone pain, skin changes and other symptoms.
Taken too many of the water-soluble B vitamins? Most of the supplemental vitamins will pass straight through your system, leaving you with neon-yellow urine (a sign, perhaps, that the money you spent on those multivitamins literally went to waste). However, excessive consumption of some water-soluble vitamins can still have harmful effects. Taking large doses of vitamin B6 (pyridoxine hydrochloride) can lead to damage of the peripheral nerves, which is why most vitamin supplements now have lower levels of B6.
Perhaps the oldest myth in nutrition surrounds vitamin C and the prevention of the common cold. Research shows it has no impact on how often you catch a cold, or how severe it will be. People who regularly consume enough vitamin C tend to have slightly shorter colds—as in, around half a day shorter. Once you’ve become infected, though, there’s no point in starting to take vitamin C supplements to fight it off. Zinc, however, might help you recover faster.
It’s not all bad news, though. Specific vitamin supplements can have significantly beneficial effects for specific groups of people, such as pregnant women taking folic acid (vitamin B9) supplements to lower the risks of certain birth defects in their unborn children.
Speak to your doctor first
Taking vitamin supplements is no substitute for a poor diet. However, if you think you may want to start taking a particular supplement, it’s always wise to check with a medical professional first. They will help ensure that your chosen supplement won’t affect any other medications you may be taking and can also give advice on whether it’s the best way to meet your particular needs.
For most people, though, the best way to get all the vitamins and nutrients your body needs is to eat a healthy, balanced diet with a variety of foods.