Vitamin D

Several scientific reviews have shown daily multivitamins to have a weak effect on preventing heart attacks and improving cognition. Instead of taking one pill that can't possibly fit every person's daily requirements, it’s recommended to supplement specific deficiencies or needs.

If you're worried about a particular health problem, pay no attention to your diet, or are always dieting, then search for the common vitamin weakness, and look at your diet.

Often linked to good heart health, it’s been recently suggested by studies that those with the lowest levels of fish oil (specifically EPA and DHA) have the highest risk of heart disease. Research also suggests that it helps with brain development and also mental illnesses.

Given its safety, price, and potential benefits, the odds are that this is a product worth taking. Algae oil is a good vegetarian alternative for fish oil.

Joint pain and osteoarthritis are commonly treated with glucosamine, and it helps with pain relief and slowing down arthritis.

Be sure you are using glucosamine sulfate, as glucosamine hydrochloride has been shown to be less effective. 

Whey protein has been shown to help aging men increase or preserve muscle mass, which is very important for mobility and overall health. To find out if you should use it, work out whether or not you are not eating enough regular protein.