When I was plagued by immune dysfunction that left me susceptible to viruses, infections and allergies, I improved my health by reducing sugar consumption, even natural sweets such as fruit.

Sugar weakens the immune system, and recent evidence shows that excessive sugar consumption is implicated in more than 60 ailments. A book to be published in September, Get The Sugar Out (Harmony Books) by Ann Louise Gittleman, M.S., will divulge forgotten information that’s been stacked against sugar.

How Sugar Weakens Immunity

Excessive sugar consumption suppresses immune function directly and indirectly, studies show. Just 100 grams of sugar in any form decreases the germ-killing ability of white blood cells for up to five hours after ingestion (American Journal of Clinical Nutrition, 1973, vol. 26). Sugar also reduces production of antibodies — proteins that combine with and deactivate foreign invaders such as viruses. In addition, excessive sugar interferes with transport of vitamin C, blocks absorption or increases excretion of many minerals, and neutralizes action of essential fatty acids — all of which further weaken the immune system.

Evidence linking sugar intake to weakened immunity is so strong, in fact, that Robert Crayhon, author of Nutrition Made Simple (M. Evans and Co.), says avoiding sugar is “the most important strategy to employ to keep your immune system strong.”

Besides inhibiting the body’s ability to defend itself against illness, overindulging in sugar may cause deadly diseases. According to Get The Sugar Out, researchers in the 1970s presented evidence that increases in cardiovascular disease and diabetes could be traced to accelerated sugar and refined carbohydrate intake. Epidemiological evidence shows sugar is a more likely cause of heart disease than fat, according to John Yudkin, M.D., who cites studies to this effect in Sweet and Dangerous (Wyden Books).

Recent research backs these theories, showing a strong connection between high levels of insulin in the blood and heart disease, obesity and diabetes. Insulin is the hormone the body produces when sugar is eaten, and the more sugar you eat, the higher your insulin levels will be. High insulin levels contribute to the development of the following heart disease risk factors: obesity, diabetes, high blood pressure, high triglyceride levels and low levels of HDL cholesterol (the “good cholesterol”), according to Gerald Reaven, Ph.D., a Stanford University researcher who’s studied insulin for three decades.

Sugar appears to play a role in the development of cancer, too. While sugar hasn’t been shown to actually cause healthy cells to become cancerous, once cancer cells are formed they may feed directly on glucose. Sugar consumption raises glucose in the blood and may therefore accelerate tumor growth. “This constant intravenous fusion of cancer fuel is a primary reason for our cancer incidence,” writes Patrick Quillin, Ph.D., R.D., in Beating Cancer With Nutrition (Nutrition Times Press).

Other health conditions related to sugar are yeast and parasitic infections, hypoglycemia, emotional problems, and increased risk of osteoporosis and kidney stones.

Sweet Hazards

Besides affecting how you feel, sugar can influence how you look. Sweets play a part in obesity because they contain only empty calories. Even natural sweeteners and too much fruit can lead to weight gain because of the fat-promoting hormone insulin. When you eat any form of sugar, your pancreas responds by producing insulin, a hormone designed to take excess sugar out of the bloodstream and move it into fat storage. Therefore, avoiding sugar is a good way to lose or maintain weight.

Skin appearance is also affected by sugar. Studies suggest acne may result from faulty sugar metabolism or lowered glucose tolerance of the skin, according to Michael T. Murray, N.D., author of Natural Alternatives to Over-The-Counter and Prescription Drugs (Wm. Morrow). Murray says a researcher who’s studied the role of sugar sensitivity in acne uses the term “skin diabetes” to describe the disorder. Based on these findings, Murray advises individuals afflicted with acne to eliminate concentrated sugars from their diets.

With the amount of evidence showing sugar is harmful to our health, why haven’t we heard much about it? Gittleman, a certified nutrition specialist from Bozeman, Mont., says it’s because the vital information about sugar got lost during the fat-free craze of the 1980s. “Information about sugar was ignored by health professionals, who were sure fat was the villain causing our health problems,” says Gittleman, former nutrition director of the Pritikin Longevity Center. “After more than a decade of experimenting with fat-free, sugar-rich foods, it’s clear that avoiding all fat isn’t the answer to America’s health problems. Reducing sugar, however, is advice we all can benefit from,” she says.

Natural sweeteners such as honey and fruit juice concentrates are good substitutes for refined white sugar because they supply more vitamins and minerals. Refined sugar is stripped of virtually all its nutrients during refining, and our bodies have to use some of our own mineral reserves to digest it.

Yet, while natural sweeteners are preferable to white sugar, they still can cause weight and health problems when eaten in excess. “Many of my most health-conscious clients overdo it on the natural sweeteners,” says Gittleman. “The idea isn’t to substitute the overuse of one form of sugar for another, but to gradually and permanently cut down on all forms of sugar to improve your health.”

To lose weight, boost immunity or reduce your risks of disease, start slashing the sugar in your diet by following these guidelines from Get The Sugar Out:

  • Eliminate refined white sugar from your diet. Use natural sweeteners such as date sugar, maple syrup and barley malt in place of refined sugar.
  • Gradually reduce the amount of natural sweeteners you use to the bare minimum.
  • Avoid using artificial sweeteners, which are associated with unpleasant side effects and health risks.
  • Read food labels and try to keep your total daily intake of sugars to under 40 grams. If you have immune dysfunction or any type of serious ailment, keep your daily intake below 20 grams.
  • Avoid sugar-rich processed foods. Instead, emphasize unrefined whole foods such as fish, lean meats, whole grains, legumes and vegetables.
  • Choose sweets that have less than five grams of sugars per serving and preferably ones that contain blood sugar-balancing fiber, protein and fat to slow down the release of sugar in your system.
  • Satisfy your sweet tooth mainly with natural, sugar-rich, fresh fruit and sweet vegetables such as carrots, bell peppers or winter squash in moderate amounts — no more than two to three servings daily.
  • Treat yourself to sweet experiences in place of sweet food. Sugar treats no longer seem so necessary when you allow yourself time for healthy indulgences.