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Nothing feels better than a good night’s sleep. New research suggests that good sleep may be essential in maintaining a healthy immune system.

Researchers at the Laval Univer-sity Cancer Research Center in Québec, Canada followed 19 adults with healthy sleep schedules and compared them to 17 adults with difficulty sleeping (insomnia). They found that the insomnia group had significantly lower levels of CD3+, CD4+, and CD8+ cells, which are essential components of our immune defense system.

Insomnia is a common condition, chronically affecting an estimated 9-12% of the adult population. The condition may involve difficulty falling asleep, frequent or prolonged nighttime awakenings, early morning awakening with an inability to return to sleep, or a combination of these problems. Previous studies have shown that insomnia is associated with more frequent medical problems, including increased need for medical consultations and hospitalizations.

“It has been believed since ancient times that sleep loss can lead to illness,” said the researchers in their report.* “Although the present study was not designed to verify that broad hypothesis, it suggests that chronic insomnia affects host defenses.”

Refer to the Insomnia protocol in the new edition of Disease Prevention and Treatment for information about correcting sleep disorders.

—Marc Ellman, M.D.

A strict, low-fat diet high in soy protein, viscous fibers, nuts, and plant sterols was found to be just as effective in lowering cholesterol as a commonly prescribed medication, according to a study published in the Journal of the American Medical Association.1 What’s more, this diet also lowered the blood levels of C-reactive protein, an inflammatory marker in the body that has been linked to cardiovascular disease.

For their study, Canadian researchers randomized 46 adults with high cholesterol into three groups. The first group consumed a diet very low in saturated fat; the second group received the same diet, but also took 20 mg per day of lovastatin (a first-generation statin-type anti-cholesterol drug); and the third group consumed a diet high in plant sterols, soy protein, viscous fibers, and almonds. At the end of the four-week study period, the researchers found that patients in the last group had similar lowered cholesterol and reduced c-reactive protein levels as the lovastatin group.
“About half of the people currently taking statin drugs to lower cholesterol could reach their blood cholesterol target or goal by using diet alone,” James W. Anderson, M.D., told Life Extension magazine. Dr. Anderson, who wrote a commentary accompanying the research article,2 is Professor of Medicine & Clinical Nutrition at the University of Kentucky and President of the Obesity Research Network.

“This requires careful avoidance of animal fat and cholesterol, a generous intake of soluble fiber such as oatmeal, oat bran, and psyllium, use of 10 grams of soy protein twice daily, such as from a soy cereal, protein bar, or soy nuts, and use of plant sterols or stanols such as from four Benecol© gelcaps every day. This regimen will decrease the LDL—or bad—cholesterol by 30%. Because of the expense, aversion to taking unnecessary medication, and side effects such as muscle pains and liver problems, many people will choose a more rigorous diet instead of taking the statin pills,” said Dr. Anderson.

—Carmia Borek, Ph.D.

The nighttime production of the hormone melatonin by the brain’s pineal gland may help prevent the growth of human breast cancer by blocking the tumor’s uptake of dietary linoleic acid, according to an article published in Breast Cancer Research and Treatment (June 2003).

Linoleic acid is an essential polyunsaturated fatty acid consumed at high levels in the Western diet. It has been shown to stimulate the development of breast and other cancers. A group of researchers at the Bassett Re-search Institute in Cooperstown, NY, believes that the growth of breast cancer and other malignancies is a net balance between stimulation during the day by growth factors such as linoleic acid and inhibition during the night by melatonin.

To further explore this relationship, the Bassett group exposed rats implanted with human breast cancer tissue to varying light situations. They found that those rats that were constantly exposed to bright light demonstrated a seven-fold increase in breast cancer growth as compared to rats on an alternating light-dark cycle. This is believed to be due to increased tumor uptake of linoleic acid from the lack of melatonin. Conversely, human breast cancers subjected to normal nighttime levels of melatonin demonstrated a nearly 70% decrease in growth, as well as decreased linoleic acid uptake and metabolism.

“This is the first biological evidence for a potential link between constant light exposure and increased human breast oncogenesis involving melatonin suppression and stimulation of tumor linoleic acid metabolism,” said the researchers in their article.

“You can essentially say that cancer cells are put to sleep at night by melatonin, but that they get their wake-up call during the day when there isn’t enough melatonin around to block linoleic acid’s stimulatory action,” lead researcher David Blask, M.D., Ph.D., told Life Extension magazine. “The melatonin signal at night is a key to the circadian regulation of cancer growth and we now know that 75-90% of human breast cancers have specific receptors for this signal.”

These findings may explain the link found in previous research between increased risk of breast and colon cancer in nurses who work rotating shifts. It is hypothesized that these nurses may be suppressing their melatonin production because of their increased exposure to light at night. In fact, research has shown that the risk of breast cancer is lower in blind women, who cannot detect light at night.

“Our study provides the first experimental evidence in a model system of human cancer to support the hypothesis that melatonin suppression in shift workers by light at night may be a major factor responsible for their increased risk of breast and colorectal cancer possibly because cells are taking up more linoleic acid than usual over the course of the day,” Blask explained.

“These findings help to make a stronger case that interactions between biological clock function, light-dark cycles, and diet will increasingly need to be taken into consideration by oncologists and others when making recommendations and decisions regarding cancer prevention and treatment strategies,” said Blask.*

—Carmia Borek, Ph.D.