Factsheet


Lactose Intolerance
The majority of people—about three-quarters of the world’s human population—are lactose intolerant: that is, they genetically lack the enzymes needed to break lactose down into the simpler forms of glucose and galactose and thus absorb these sugars into the bloodstream. (1) As a result, drinking milk or consuming dairy products causes these individuals to experience gastrointestinal pains, indigestion, gas, diarrhea and other unpleasant symptoms. 

Forty years ago, it was widely believed that almost everyone possessed the enzymes needed to digest lactose, but research done in the mid-1960s and afterward confirmed that most humans lose them after being weaned (usually between the ages of two and five). Studies since then have shown that significant numbers of many racial and ethnic groups (approximately 90% of Asians, 70% of African Americans, 50-80% of Latinos, and so on) are lactose intolerant. (2-5) Those who retain the ability to digest lactose beyond early childhood (i.e., about 85% of Caucasians and much smaller fractions of other racial groups) are only able to do so because of an inherited genetic mutation. (6)

Even though about one-quarter of adults in the U.S. are lactose intolerant (1), the federal dietary guidelines used as the basis for all public nutritional programs (such as subsidized school lunch plans) recommend two to three 8-oz. servings of milk a day. Disclaimers about lactose intolerance notwithstanding, such recommendations give the false impression that milk is a necessary part of a healthy diet when in fact it is making people sick. Unfortunately, as a result of the shared economic interests of federal agencies and the dairy industry, government policy continues to reflect the cultural and racial prejudices of bygone eras rather than sound science.

The Dairy Deception

According to the U.S. Department of Agriculture’s (USDA’s) Dietary Guidelines for Americans, a “healthy diet” includes “fat-free or low-fat milk and milk products” along with other animal products like meat and eggs. (7) The USDA’s food pyramid reflects this, claiming that “Diets rich in milk and milk products help build and maintain bone mass throughout the lifecycle. This may reduce the risk of osteoporosis.” 

Yet this assertion is misleading if not dangerous, as studies show that the highest rates of osteoporosis are found in those countries with the highest consumption of animal products. (9) According to medical researcher Dr. John McDougall, “On a nation-by-nation basis, people who consume the most calcium have the weakest bones and the highest rates of osteoporosis…Only in those places where calcium and protein are eaten in relatively high quantities does a deficiency of bone calcium exist, due to an excess of animal protein.” The evidence overwhelmingly suggests that rather than building strong bones, milk and other animal products actually prevent calcium from being absorbed into the body so that it is passed out in urination. (10)

There are plenty of plant-based foods—including green leafy vegetables (like broccoli, kale and collards), beans, and fortified soymilk and juices—that are excellent sources of calcium which the body is much better equipped to absorb. Rather than focusing on calcium intake, people can reduce their risk of developing osteoporosis by making healthy lifestyle choices like exercising regularly and avoiding alcohol, tobacco and caffeine.

Other Dairy Drawbacks

In addition to being linked to osteoporosis, research shows that dairy consumption also contributes to cancer (11-14), heart disease (15-16), diabetes (17-18) and other serious health disorders. According to the American Gastroenterological Association, cow’s milk is also the number one cause of food allergies among infants and children. (19) 

Besides improved health, there are other compelling reasons to avoid dairy products. For instance, dairy cows on factory farms suffer from being forcibly impregnated, hooked up to milk machines, and slaughtered for hamburger meat when their productivity declines. Raising cattle for meat and dairy is also environmentally destructive. As one example of this, a new report issued by the United Nations warns that the cattle industry produces more greenhouse gasses than any other human activity—more than the emissions of all the cars in the world combined. (20) 

While milk harms our bodies, raising cows to produce it also hurts animals and imperils the life support systems of our planet. Given these realities and the fact that people can get all the essential nutrients they need from plant based foods, there is no reason for anyone—lactose intolerant or not—to drink milk or consume dairy products.

References:

1. Hertzler SR, Huynh BCL, Savaiano DA. How much lactose is low lactose? Journal of the American Dietetic Association, 1996;96:243-6.
2. Cuatrecasas P, Lockwood DH, Caldwell JR. Lactase deficiency in the adult: a common occurrence. Lancet, 1965;1:14-8.
3. Huang SS, Bayless TM. Milk and lactose intolerance in healthy Orientals. Science, 1968;160:83-4.
4. Woteki CE, Weser E, Young EA. Lactose malabsorption in Mexican-American adults. American Journal of Clinical Nutrition, 1977;30:470-5.
5. Newcomer AD, Gordon H, Thomas PJ, McGill DG. Family studies of lactase deficiency in the American Indian. Gastroenterology, 1977;73:985-8.
6. Scrimshaw NS, Murray EB. The acceptability of milk and milk products in populations with a high prevalence of lactose intolerance. American Journal of Clinical Nutrition, 1988;48:1083-5.
7. www.mypyramid.gov/guidelines/index.html 
8. www.mypyramid.gov/pyramid/milk_why.html 
9. Abelow BJ, Holford TR, Insogna KL. Cross-cultural association between dietary animal protein and hip fracture: a hypothesis. California Tissue International, 1992;50:14-8.
10. Nordin BEC, Need AG, Morris HA, Horowitz M. The nature and significance of the relationship between urinary sodium and urinary calcium in women. The Journal of Nutrition, 1993;123:1615-22.
11. Cramer DW, Harlow BL, Willet WC. Galactose consumption and metabolism in relation to the risk of ovarian cancer. Lancet, 1989;2:66-71.
12. Outwater JL, Nicholson A, Barnard N. Dairy products and breast cancer: the IGF-1, estrogen, and bGH hypothesis. Medical Hypothesis, 1997;48:453-61.
13. Chan JM, Stampfer MJ, Giovannucci E, et al. Plasma insulin-like growth factor-1 and prostate cancer risk: a prospective study. Science, 1998;279:563-5.
14. World Cancer Research Fund. Food, Nutrition, and the Prevention of Cancer: A Global Perspective. American Institute of Cancer Research. Washington, D.C.: 1997.
15. Pennington JAT. Bowes and Churches Food Values of Portions Commonly Used, 17th ed. New York: Lippincott, 1998.
16. Ornish D, Brown SE, Scherwitz LW, Billings JH, Armstrong WT, Ports TA. Can lifestyle changes reverse coronary heart disease? Lancet 1990;336:129-33.
17. Scott FW. Cow milk and insulin-dependent diabetes mellitus: is there a relationship? American Journal of Clinical Nutrition, 1990;51:489-91.
18. Karjalainen J, Martin JM, Knip M, et al. A bovine albumin peptide as a possible trigger of insulin-dependent diabetes mellitus. New England Journal of Medicine, 1992;327:302-7.
19. American Gastroenterological Association, “American Gastroenterological Association Medical Position Statement: Guidelines for the Evaluation of Food Allergies,” Gastroenterology, 120 (2001): 1023-5.
20. H. Steinfeld, P. Gerber, T. Wassenaar, V. Castel, M. Rosales, C. de Haan. Livestock’s long shadow: Environmental issues and options, UN Food and Agriculture Organization, 2006: www.virtualcentre.org/en/library/key_pub/longshad/A0701E00.htm 








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