Nutritional suggestions to benefit fertility

Defined as the inability to achieve a pregnancy after at least a year of trying, infertility affects more than 20 percent of North American couples. Read on to see how nutrition can play a role in your fertility.

Experts cannot explain why the infertility rate has almost doubled in the last 25 years, but at least three factors stand out:

• the growing trend for couples to delay marriage and parenthood until past their most fertile years
• the rise in sexually transmitted diseases
• a puzzling drop in sperm production

Many couples assume that infertility rests with the woman, but men are just as likely to be infertile. While nutrition is not a leading cause of infertility, consuming a healthy diet enhances the chance of conceiving and delivering a healthy baby. Also, alcohol and smoking are known to reduce fertility in both women and men; a recent study indicated that coffee may have a similar effect.

The leading cause of female infertility is the failure to ovulate, which may be influenced by various factors, like diet or hormonal imbalances. Women who are very thin or markedly overweight may not ovulate because body fat is closely associated with estrogen levels.

• Conception and weight. Any woman who is considering becoming pregnant should try to achieve her ideal weight before conception. A woman who is underweight when she conceives is likely to have problems like anemia during pregnancy. The baby may also be smaller than normal and is more at risk for health problems. Conversely, dieting during pregnancy could be dangerous to the fetus. An overweight woman should diet before trying to conceive to lower her risk of high blood pressure or diabetes during pregnancy
• Essential nutrients. Women who take oral contraceptives are likely to experience temporary infertility until their hormonal levels return to normal. Long-term use can result in reduced reserves of folate; vitamins B6, B12, C and E; and calcium, zinc and other minerals. The woman's diet should emphasize foods that are rich in these nutrients — fruits and vegetables, milk, fortified breads and cereals, lean meat, poultry and seafood

A low sperm count is the major cause of male infertility, and for unknown reasons, men worldwide are producing fewer sperm these days. Some scientists believe certain pesticides, which have estrogen-like effects, may be linked to the declining count. Alcohol and tobacco lower sperm production.

• Zinc. Inadequate zinc may lower male fertility; a recent study found that men who ­consumed 1.4 milligrams daily produced fewer sperm and had lower levels of the male hormone testosterone than men whose daily zinc intake was 10.4 milligrams. The Recommended Dietary Allowance for adult men is 11 milligrams
• Vitamin C. Inadequate intake may impair male fertility. One study correlated low levels of vitamin C with an increased tendency of sperm to clump together, a problem that all but disappeared after three weeks of taking supplements
• Folate. Researchers studied a group of healthy men who had low intakes of fruits and vegetables and did not take supplements. Their study suggests that low levels of folate in these men were associated with decreased sperm count and decreased sperm density. The vitamin's role is unclear, but researchers believe normalizing folate levels through diet may offset diminished sperm levels. The best food sources are dark green vegetables, orange juice, liver, dried peas and beans. Other evidence suggests that vitamin B12 (found in animal products) may improve sperm count and motility, even in men who are not B12 deficient

While the cause of infertility may not lie in nutrition, ensuring your body is as healthy as you can through your diet can only benefit you and your chances of conceiving. Eating a healthy, well-balanced diet, limiting caffeine and avoiding alcohol and smoking will help to make sure you're on the right nutritional path.