Cholesterol gets a bad rap. High cholesterol is linked to heart attack and stroke, and low cholesterol has been shown to cause hormone imbalances and decreased sex drive. But the fat-based substance is necessary for some of our bodies' basic functions. Cholesterol helps build cell membranes; contributes to rescue work of blood vessels; protects nerve fibers; and aids the production of vitamin D, bile acids and hormones that are essential to fertility.
"Cholesterol is a precursor for steroid hormones, such as estrogen and testosterone, which are very important for men and women," says Dr. Lauren Roth, assistant professor of obstetrics and gynecology in the Division of Reproductive Endocrinology and Fertility at the University of Colorado School of Medicine. "Hormones are involved with reproduction, maturation of eggs and sperm and preparing the uterus for the embryo."
Cholesterol combines with proteins in the blood stream to create high-density lipoprotein (HDL) and low-density lipoprotein (LDL) particles. LDL delivers cholesterol to body tissues, and although it is considered the "bad cholesterol," LDL has been shown to aid in muscle building. The "good cholesterol," HDL, delivers cholesterol to the adrenals and ovaries for hormone production and takes up excess cholesterol for processing and disposal in the liver. Triglycerides, the smallest particles, are incorporated into both HDL and LDL.
We get cholesterol in two ways: the liver makes the proper amount the body needs, and we consume more in foods that come from animals, including meat, chicken, fish, eggs and dairy products.
"Normal cholesterol level ranges depend on individual risk factors for heart disease," Dr. Roth says. "For a woman with no risk factors, her ideal HDL level is greater than 50 mg/dL, her ideal LDL level is between 100 and 129 mg/dL, and her ideal triglyceride level is less than 150 mg/dL."
There are many ways to maintain healthy cholesterol levels. Dr. Roth emphasizes a balanced diet: "Decrease saturated fats and increase fiber intake." She also suggests consuming fish oil two to three times per week, avoiding high-mercury fish, eating nuts and drinking green tea.
"Moderate alcohol intake can also safely increase levels of good cholesterol," Dr. Roth says. "Limit it to one drink per day for women and one to two drinks per day for men."
"Reducing bad cholesterol affects good cholesterol, so exercise is important," Dr. Roth says. She recommends aerobic exercise, such as walking, running, swimming, cycling and dancing, for 30 minutes per day, several days per week.
According to Dr. Roth, the direct impact of cholesterol on fertility hasn't been determined conclusively; however, there is evidence that statins, drugs used to lower cholesterol, cause abnormalities in fetal development.
"If you are taking a statin and want to try to get pregnant, stop taking the drug at least three months before trying to conceive," Dr. Roth says.
"It's important to consult with your doctor to talk about your health and the risks involved with trying to get pregnant," Dr. Roth says. "Overall, a healthy lifestyle will improve your physical and mental state and decrease the potential negative impacts cholesterol has on fertility."