There is scant scientific evidence for many of the claims put forth by supplement makers, from instant overnight weight loss to cures for cancer. However, there have been some supplements that have stood the test of robust scientific research. Several stand out in this respect, and are probably worth adding to your diet. These include vitamin D, fish oil, and green tea.
There have been several recent studies suggesting that vitamin D may help prevent cancer. This vital nutrient is produced by the body when the skin is exposed to sunlight, and vitamin D deficiency symptoms include rickets in children and soft bones in adults. Some studies have also shown higher incidences of cancer in countries that get less sunshine, suggesting a possible link between the two. Research is ongoing and there are no definite conclusions yet, but since vitamin D is safe to take in normal amounts, it might be a good supplement to add to your diet. Especially if you don’t get much sun.
Omega 3 fatty acids are nutrients found in fatty fish like salmon and tuna, and there is a proven link between low amounts of omega 3 and the risk of cardiovascular illness like heart attacks and strokes. Accordingly, it may be a healthy choice to either eat more fish or begin taking fish oil supplements. Since fish contains mercury, fish oil is a convenient and relatively healthy alternative.
Finally, green tea has been suggested as a possible way to lower cholesterol. While there is no substitute for eating a diet low in saturated fat, there have been many studies that have shown that drinking green tea daily can improve cholesterol and hence cardiovascular health. Additionally, it is probably a safe supplement to take regularly, and it may also increase metabolism and help enhance weight loss, although this effect is probably minimal.