Prenatal vitamins have an array of beneficial vitamins and minerals in them, and some consider them to be the best and most powerful vitamins available. Many people assume that since prenatal vitamins can support a woman as well as a growing baby, they must be safe for anyone to take. However, there are a few key differences between a man and a woman's body that will cause several different reactions to prenatal vitamins. While many vitamins in prenatal vitamins are harmless or beneficial for men's health, there are several vitamins and minerals that can have adverse efffects.

Decreased Risk of Heart Attack

Vitamin D supplementation in men has been shown to decrease men's risk of having a heart attack. Prenatal vitamins usually supply the appropriate amount of vitamin D for both men and women.

Increased Fracture Risk

A high level of vitamin A intake in men--particularly men in their forties and fifties--has been shown to dramatically increase the risk bone fracture. While not all prenatal vitamins include high levels of vitamin A, many do and it is important to check the label before taking any prenatal vitamin. Men should not have more than 900 mg of vitamin A per day.

Decreased Chance of Birth Defects

For couples trying to get pregnant, folate in prenatal vitamins can benefit both men and women. Increased folate intake in men has been shown to decrease the risk of birth defects in their children.

Constipation

Men generally don't need as much iron as women because they don't lose iron through menstruation like women do. Excess amounts of iron in prenatal vitamins can cause stomach pain, nausea and constipation in men. High levels of iron are also linked to heart disease in men.

Increased Risk of Prostate Cancer

While most prenatal vitamins include only vitamins and essential minerals, some include omega supplements as well. Omega 3 is derived from flax oil and has been shown to increase the risk of prostate cancer in men. Omega 3 derived from fish oil, on the other hand, has been shown to inhibit prostate cancer, so it is important to determine what type of Omega 3 (if any) is in prenatal vitamins before taking them.

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