ITAMIN D. Vitamin D becomes even more important with age, because it's needed to absorb calcium and helps prevent weak muscles and bones. Many men do not get enough exposure to the sun, which is needed for the body to produce vitamin D. It can be hard to get enough vitamin D from food. Most men can benefit from taking 1,000 IU of vitamin D daily. Too much vitamin D can cause fatigue and muscle weakness, so you should stay below 2,000 IU unless your doctor advises otherwise. Good food sources for vitamin D include salmon, sardines, cod liver oil, milk, cheese, egg yolk, orange juice, yogurt, and fortified breakfast cereal.