Atkins Diet Makes PMS Worse?

The Early Show, Dr. Neal Barnard
CBS/The Early Show
Women dieters beware. A low-carb diet can make premenstrual symptoms much worse.

Dr. Neal Barnard, president of the Physicians Committee for Responsible Medicine, explains from The Early Show's Washington bureau on Friday that a low-fat, vegetarian diet reduces menstrual pain and other premenstrual symptoms.

Premenstrual Syndrome, or PMS, is usually characterized by a combination of physical and mood changes, including emotional and behavioral changes — bloating or water retention and cramping pain. Other symptoms can include breast tenderness, headache, insomnia, digestive upsets, heart palpitations and dizziness.

The American College of Obstetrics and Gynecology says that approximately 80 percent of women have emotional or physical changes in advance of their menstrual periods, and 20 to 40 percent find them problematic. Some theorize the underlying cause of PMS could be due to hormonal imbalance, deficiencies in essential fatty acids, vitamin B6, calcium and adrenal gland dysfunction. The National Institute of Mental Health calls PMS "an abnormal response to normal hormonal changes."

Barnard says that a diet that is high in fat, such as the low-carb Atkins diet, is likely to exacerbate if not cause premenstrual syndrome symptoms in women who are prone to suffering from PMS. Diet is known to influence hormone levels. And low-fat vegetarian diets in particular have been shown to reduce estrogen levels, he explains.

An increase in fat consumption and a decrease in low-fat vegetable consumption contributes to PMS symptoms, according to Barnard. Improving nutritional habits, he says however, effectively decreases PMS. In a study conducted by Barnard, a low fat-diet was reported to reduce estrogen levels, menstrual pain and other premenstrual symptoms like emotional changes and bloating. Also, PMS symptoms were lessened, and many women experienced significant relief, especially with water retention and concentration. Study participants had increased energy, lower cholesterol levels and weight reduction.

So far, experts don't know the exact cause of premenstrual syndrome, or PMS, but there are clear links between PMS and the hormonal levels of the menstrual cycle. There is a rise in estrogen and progesterone at the end of a woman's cycle and then a rapid drop of the two right before her period.

Barnard observes if there's a lot of animal fat in a woman's diet, estrogen levels rise all the time and cause a big downward swing when the time of the month comes for estrogen to drop before a woman's period. Barnard says that bigger-than-normal swing is what exacerbates the symptoms of PMS.

He adds that contrary to fad low-carb diets like Atkins, the dietary goal for women should be to smooth out the human roller coaster many experience each month. Barnard advises to cut fat dramatically and try to stick to a low-fat plant-based diet to keep hormones in equilibrium and lessen the impact of PMS.

Some health experts say the Atkins diet may also have other long-term risks that are currently unknown. High-fat diet has long been thought to increase the risk of colon cancer. And the Harvard School of Public Health has shown that a high-fat diet increases the risk of hormone-related breast cancer.

Most experts do agree a good diet for women looking to decrease the symptoms of PMS consists of five servings of fruits and vegetables per day and minimal animal fat.