We analyse global research on how certain vitamins, minerals and other nutrients affect the risk of developing cancer.
There is strong evidence that:
For high-dose beta-carotene supplements and calcium supplements, conclusions can be drawn only for the doses that were investigated.
Carbohydrates, fats and proteins are macronutrients that supply energy and are essential for tissue structure and function as well as physical and mental growth and development. These macronutrients can be subdivided into:
These constituent parts have different metabolic, physiological and biochemical effects, alone or in combination. Glycaemic index and glycaemic load are terms used to characterise foods and diets based on their effects on blood glucose levels.
A series of substances that don’t supply energy have been identified as also being vital to life, typically in small amounts: these are vitamins, minerals and trace elements.
As well as being contained in foods, these micronutrients are also available as supplements (usually in pill or powder form), and some are consumed in doses far in excess of what could be absorbed from food in any typical diet.
Vitamins are organic molecules – which may be fat or water soluble – that are needed for metabolism. However, most cannot be made in the body and so must be supplied in the diet. They each have specific functions in the body.
Vitamins A (retinol), D, E and K are fat soluble and can only be digested, absorbed and transported in conjunction with fats. They are found in liver, egg yolk and oily fish, and in the fat in milk and dairy products, animal fats and vegetable oils.
Fat-soluble vitamins are stored in the liver and in body fat stores. For this reason, they do not need to be consumed every day. Partly for the same reason, continuous high intakes, especially of retinol and vitamin D, can lead to excess accumulation and toxicity.
Vitamin C and the B vitamins are water soluble. The B group includes thiamin (vitamin B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9) and cobalamin (B12).
Excess amounts of water-soluble vitamins are generally not toxic because they are excreted in the urine rather than stored in the body. This also means that they generally have to be consumed more frequently than fat-soluble vitamins.
Foods of plant origin are important sources of water-soluble vitamins: for example, grains, vegetables, fruit, some roots and tubers and pulses. They can be destroyed by heat or exposure to the air, or lost by leaching during cooking, for instance when vegetables are boiled.
In 2018, we produced the Diet and Cancer Report, the third in our series of major reports looking at the many ways in which our diets, and how active we are, affect our cancer risk.
You can find out much more about vitamins, minerals, other nutrients and the risk of cancer by downloading a pdf of the relevant chapter in the 2018 report. Please note, however, that this webpage may have been updated since the report was published.