You may have heard that multivitamins are a “magic pill” for your health, and if you’ve been taking them for some time you might be disappointed to learn that there’s no secret cure all for good health.

Ultimately, nothing can replace a balanced, varied diet and regular exercise. Having said that, vitamins are essential organic substances that your body’s cells need to function properly. A deficiency of any one of the 13 essential vitamins can cause serious health problems, including nutrient deficiencies and immune system disorders.

The good news is that most vitamins are readily available in foods of the kind you buy at your supermarket, for example. They’re also often found in fortified foods, which are made with a special blend of nutrients to boost up your intake.

Many of the vitamins you get from food are much better absorbed than the synthetic ones in supplements, so you won’t have to take extra pills. This is particularly true for the B-complex vitamins, such as folic acid and niacin. However, the quality of the food you are consuming is key. Has it been transported a long distance? Has it been stored or shelved for a long period? Has it been processed? If the answer to any of these questions is “yes”, than the nutrient content of the food is likely to be fairly low. In this case, food form vitamins are a good way to supplement your daily nutrient intake. In other words, vitamins that contain natural food ingredients that are as close to their original food form as possible, with minimal processing.

If you’re pregnant, it’s especially important to make sure that you’re getting enough folic acid in your diet. Folic acid helps to prevent a baby from developing neural tube defects, such as spina bifida. It can also improve your memory and help to prevent brain aging.

Another important nutrient is vitamin K, which is essential for blood clotting and bone health. It’s not produced by your body on its own, and it’s difficult for most people to get enough of it from food alone, so a supplement is recommended.

The B vitamins include B6 (pyridoxine), which supports biochemical reactions in your immune system; B12 (cobalamin), which is involved in metabolising protein and carbohydrates; and biotin, which helps to maintain healthy skin and nerves.

You’ll find the B vitamins in leafy green vegetables, fruits, legumes, nuts and fortified breads, cereals and other foods. It’s also a good idea to eat some fish and chicken every day, which are high in omega-3 fatty acids, which can reduce the risk of heart disease, obesity and diabetes, among other health issues.

But it’s important to understand that taking more than the recommended daily amount of certain vitamins can be dangerous. For instance, too much retinol (Vitamin A) can cause nausea, vomiting and blurred vision. It’s also possible to overdose on vitamin C or E.

It’s a myth that you have to take multivitamins with food because they are water-soluble and will be absorbed even when you don’t have anything in your stomach. It’s actually better to eat some food before taking a multivitamin containing fat-soluble vitamins, such as A, D, E and K, because they can only be absorbed when they’re paired with some fat.

Some vitamins and minerals can interfere with each other, so it’s important to know which are safe when taken together, and what’s best for your specific situation. If you’re breastfeeding, talk to your doctor about which vitamins are best to supplement with.