The Harmful Component in Milk May Well Be Sugar Called Galactose

Most scientists no longer believe that dietary cholesterol and saturated fats are particularly harmful. High blood levels of cholesterol and saturated fat are strong predictors for heart disease, but most of the cholesterol and saturated fat in your bloodstream are made by your liver from the sugar and alcohol that you consume, and do not come from the saturated fat and cholesterol in foods. It appears that sugar is the most health-damaging factor in the North American diet.

Galactose, the sugar in milk, causes the same oxidative damage and chronic inflammation that is associated with diabetes, heart attacks, certain cancers, and bone loss. People who drink milk have increased urine levels of 8-iso-PGF2a (a marker of oxidative stress) and serum interleukin 6, a marker of inflammation. Chronic exposure of mice, rats, and fruit flies to galactose caused the animals and their cells to age at a faster than normal rate. Their cells had signs of aging: shorter telomeres and DNA damage. More on Why Milk May Be Harmful

Benefits of Yogurt and Cheese

(Felipe Caparrós Cruz/iStock)
People who eat a lot of cheese have high levels of healthful intestinal bacteria that can help to prevent diabetes and heart attacks (Felipe Caparrós Cruz/iStock)


Several studies have shown that milk is associated with increased risk for heart attacks, but fermented dairy products such as yogurt and cheese have not been associated with increased risk for heart attacks, diabetes or bone loss. Yogurt and cheese have very low levels of lactose and galactose, because fermenting milk breaks down galactose so that almost none is left. Several studies have shown that cheese reduces blood levels of the “bad” LDL cholesterol when compared to butter with the same fat content.

Yogurt and cheese may help to prevent heart attacks. Of 27,000 people, ages 45 to 74, those who ate cheese and yogurt had a 25 percent lower risk of Type-2 diabetes than those who did not eat these fermented dairy products. Fermented dairy products encourage the growth of healthful intestinal bacteria that convert them in the intestines to butyrate to prevent formation of the bad LDL cholesterol. People who eat a lot of cheese have high levels of healthful intestinal bacteria that can help to prevent diabetes and heart attacks, very high levels of butyrate in their stool and urine (beneficial), and lower levels of the bad LDL cholesterol that is associated with increased heart attack risk.

Harm from All Sugared Drinks, Including Milk

Eating or drinking sugar can cause a high rise in blood sugar that can damage all of the cells in your body. Sugar in drinks causes a higher rise in blood sugar levels than sugar in food. When food reaches your stomach, the pyloric sphincter muscle at the end of the stomach closes and only liquid soup is allowed to pass into your intestines. Liquids pass quickly into your intestines and then into your bloodstream, while solid foods stay a long time in your stomach, so blood sugar levels rise more slowly.

Sugared drinks are associated with increased risk for obesity, diabetes, inflammation-related pain, heart attacks and certain cancers. An 8-ounce glass of two percent low-fat milk contains: * 122 calories, more than an 8-ounce glass of soda, * more than three teaspoons of sugar, and * more than the total daily recommendation of sugar for children. Chocolate milk and other milk-based beverages often have even more sugar added to make them taste better. Yogurt and other fermented milk beverages do not need to be classified as sugared drinks because the fermentation process breaks down galactose (the main sugar in milk). However, check the list of ingredients; fruit-flavored yogurts, frozen yogurt and other yogurt products often contain added sugars.

What These Studies Mean for You

These studies do not prove that milk causes diabetes or heart attacks, or that cheese and yogurt help to prevent them. They raise questions that suggest that you should limit the amount of milk that you drink, but that you do not need to avoid cheese or yogurt.

Gabe Mirkin, M.D., has been a practicing physician for over 50 years. He is board-certified in sports medicine, allergy and immunology, pediatrics, and pediatric immunology. This article was originally published on Subscribe to his free weekly Fitness & Health newsletter.