Nutritional supplements are meant to?

Nutritional supplements are  meant to ;

Provide nutrients (like   vitamins, minerals, proteins ) that (in most cases) are consumed in sufficient quantities.

Explanation:

In other words ;

They are products used to improve the diet and they often contain vitamins, minerals, herbs or amino acids.

cutting out negative people, changing their diets, exercising, taking off days from work or school, etc