Much controversy still exists over whether dairy products are healthful or harmful. However, the recent literature shows that milk is a high-sugar drink, and accumulating evidence over the last few years shows that fermented dairy products such as cheese and plain yogurt, which humans have made for more than 8000 years, may be far more healthful than milk.
Milk, butter and cream contain large amounts of the pro-inflammatory sugar, galactose, while aged cheeses and yogurt contain almost no galactose because fermentation destroys the galactose, which appears to make fermented dairy products healthful (Nutrition, Metabolism and Cardiovascular Diseases, May 21, 2018). Cheese and yogurt (with no added sugar) lower high blood sugar and insulin and are not associated with increased risk for heart attacks or diabetes (Nutr Rev, 2015;73(5):259-275) or gaining weight (BMC Med, 2014;12:215).
Galactose can cause inflammation that damages cells. When you are infected by germs, your immune cells and proteins try to kill the invading germs, but as soon as the attacking germs are gone, your immunity is supposed to dampen down. If your immunity stays active, it can use the same cells and proteins to attack you and damage your own cells. This process is called inflammation. Galactose has been shown to be the most pro-inflammatory sugar of the four sugars that can pass from the intestines into the bloodstream — glucose, fructose, mannose and galactose (Cytokine, Sept 2014;69(1):150-153). See Whole Milk or Skim? Cheese and Yogurt are Better
Milk Is a High-Sugar Drink
Many studies show that sugared drinks markedly increase risk for obesity, diabetes, heart attacks and premature death. One cup (8 ounces) of two percent low-fat milk contains:
• 122 calories, more than an 8-ounce glass of soda, and
• more than three teaspoons of sugar, which is more than the current daily recommendation of sugar for children. Chocolate milk and other milk-based beverages may have even more sugar added to make them taste better.
Several recent studies have found that milk, butter and cream are associated with increased risk for diabetes (British Journal of Nutrition, February 28, 2018;119(4):442-455). A recent study followed almost 115,000 healthy Dutch adults and found that the people most likely to develop diabetes drank milk and ate non-fermented dairy products. Those who ate primarily fermented dairy products such as yogurt and aged cheeses were less likely than average to develop pre-diabetes (British Journal of Nutrition, February 28, 2018;119(4):442-455). The authors defined pre-diabetes as a fasting blood sugar between 100 to 124 mg/dl in the U.S. (5.6 to 6.9 mmol/l in Europe), and diabetes as a fasting blood sugar >126 in the U.S. (7 mmol/l in Europe) or HbA1c >7.
Earlier studies showed that cheese is associated with reduced risk for becoming diabetic (Nutr Rev, 2015;73(S1):15-22) and eating cheese and yogurt lowers risk for type II diabetes by 25 percent (Am J Clin Nutr, April 2015). Among more than 6500 overweight people who ate a healthful Mediterranean diet of primarily plants and fish, those who also ate lots of fermented dairy products (cheese and plain yogurt) had lower markers of diabetes, such as low good HDL cholesterol and high triglycerides (Nutrition, Metabolism and Cardiovascular Diseases, May 21, 2018).
Recent studies question the dogma associating saturated fats and cholesterol in milk with heart attack risk (Arterioscler Thromb Vasc Biol, Sept 2016;36(9):2011-8; Am J Clin Nutr, Feb 2016;103(2):356-65). High-fat but galactose-free yogurt, cheese and other fermented dairy products may even help to prevent heart attacks (Journal of Agricultural and Food Chemistry, April 2015;63(10):2830-9). People who ate a lot of cheese had very high levels of healthful butyrate in their stool and urine and much lower blood levels of the bad LDL cholesterol. This means that the fermented dairy products appear to be converted by bacteria in the intestines to butyrate that help prevent food from forming the bad LDL cholesterol that is associated with increased heart attack risk (Am J Clin Nutr, Feb, 2016;103(2):356-65). The authors showed that fermented dairy products encourage the growth of healthful intestinal bacteria that may help to prevent heart attacks. Several studies have shown that cheese reduces blood levels of the “bad” LDL cholesterol when compared to butter with the same fat content.
Low-fat dairy products are more likely than high-fat dairy products to be associated with weight gain and obesity (Eur J Nutr, 2013;52(1):1-24). Skim milk may have additional milk powder added to improve taste and consistency, thus increasing its content of the pro-inflammatory sugar, galactose. Galactose appears to be a more likely culprit than saturated fats in causing obesity.
A review of the scientific literature found 18 articles following 363,557 participants for 3 to 23 years and the authors showed that yogurt and cheese, but not whole milk and cream, are associated with decreased risk for hip fractures (BMC Public Health, February 02, 2018). People who ate a lot of yogurt or cheese had a 25 to 32 percent lower risk of hip fractures than those who ate little or no cheese or yogurt. This new research shows that eating yogurt and cheese is associated with reduced risk for hip fractures; it does not show that eating yogurt or cheese prevents fractures.
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.