Leptin, insulin, ghrelin, and insulin-like growth factor I (IGF-I) are hormones thought to promote growth during neonatal development. These kinds of growth hormones are not only found in humans but in all lactating mammals. Like human mothers, cows and goats supply their offspring with certain growth factors in their milk that are neces-sary for optimal growth. But after weaning there is no dietary recom-mendation for adult mammals to drink their own bodily fluids. The same goes for human babies. In America’s most popular baby book, Dr. Spock’s Baby and Child Care, Dr. Spock points out the multiple concerns with milk consumption for babies. Some potential concerns include iron deficiency anemia, asthma, eczema, respiratory problems, ear infections, constipation, bloating, and increased risk of type-1 diabetes for children genetically vulnerable.1,2
Americans consume several types of cow’s milk (e.g., whole fat, buttermilk, 1%) in hopes to achieve good health. The thought is that milk contains protein, calcium, and other vital micronutrients necessary for bone integrity. Interesting enough, countries in the world that consume the most milk and dairy products have the highest rates of osteoporosis and hip fractures.3,4 Clinical research shows that dairy products have little or no benefit for bones.5,6,7
Although animal milks have calcium and protein their calcium is poorly absorbed and their proteins are often difficult to digest. Lactose intolerance affects 75 percent of the world population.8,9 People claim that goat’s milk is easier to digest and a good alternative for lactose intolerant individuals, but many do not know that lactose is still present. Goat’s milk also contains casein proteins, the same proteins identified in cow’s milk, which have been shown to increase IGF-I. Research shows the more IGF-I in the body the greater our cancer risk. And researchers found animal proteins influence IGF-I accumulation10 compared to plant pro-teins, which can actually decrease IGF-1 levels.11
Furthermore, looking at the nutrient differences between the types of milk you can see who won the award for fat. The National Cholesterol Education Program recommends obtaining < 7% of saturated fat per day. One 8 ounce glass of goat’s milk contains almost half of your daily supply of saturated fat. 12

I do not understand why goat’s milk is touted as a “health” food when healthier options are available? Fat intake and body fatness drive cancer progression and is one of the largest contributors to cancer risk, accord-ing to the American Institute for Cancer Research. The recommendation to drink lactating animals’ milk is based on consumer demand and culture, not science. In a physician’s heath study observing rates of prostate cancer, researchers found men who consume more milk during their lifetime significantly increased prostate cancer risk.13 Most of the milk consumed in the study was either 1% or fat-free, which shows that animal proteins can be more detrimental than fat alone.
To maximize bone integrity and lower risk of disease it is important to select foods from plant origin, not goats or cows milk. The most healthful calcium sources are green leafy vegetables and legumes, or "greens and beans" for short. Broccoli, Brussels sprouts, collards, kale, mustard greens, Swiss chard, and other greens are loaded with highly absorbable calcium and a host of other healthful nutrients. Vitamin D controls your body's use of calcium. About 15 minutes of sunlight on your skin each day normally produces all the vitamin D you need. If you get little or no sun exposure, you can get vitamin D from any multiple vitamin or other for-tified food sources (soymilk, cereals). Lastly, vitamin C helps build the bone matrix giving bones structure and support. Choose whole plant foods like oranges, red peppers, and spinach for healthful sources of vitamin C.
To learn more about foods for disease prevention, visit www.PCRM.org or www.CancerProject.org

References:
1) Saukkonen T, Virtanen SM, Karppinen M, et al. Significance of cow’s milk protein antibodies as risk factor for childhood IDDM: interaction with dietary cow’s milk intake and HLA-DQB1 genotype. Child-hood Diabetes in Finland Study Group. Dibetologia. 1998;41:72–8.
2) Kimpimaki T, Erkkola M, Korhonen S, et al. Short-term exclusive breastfeeding
predisposes young children with increased genetic risk of Type I diabetes to progressive beta-cell autoimmunity. Diabetologia. 2001;44:63–69.
3) Report of a Joint Food and Agriculture Organization of the United Nations/World Food Organiza-tion of the United Nations Expert Consultation. Human vitamin and mineral requirements. Bangkok, Thailand; September 1998. ftp://ftp.fao.org/es/esn/nutrition/Vitrni/vitrni.html (accessed 9 Nov 2006).
4) Abelow BJ, Holford TR, Insogna KL. Cross-cultural associations between dietary animal protein and hip fracture: a hypothesis. Calcif Tissue Int. 1992;50:14-18.
5) Cooper C, Campion G, Melton L. Hip fractures in the elderly: a world-wide projection. Osteoporos Int. 1992;2:285-289.
6) Riggs B, Melton L, III. Osteoporosis: etiology, diagnosis, and management, 2nd ed. Lippincott-Raven; 1995.
7) Lanou AJ, Berkow SE, Barnard ND. Calcium, dairy products, and bone health in children and young adults: a reevaluation of the evidence. Pediatrics. 2005;115(3):736-43.
8) Cuatrecasas P, Lockwood DH, Caldwell JR. Lactase deficiency in the adult: a common occurrence. Lancet. 1965:14-18.
9) Mishkin S. Dairy sensitivity, lactose malabsorption, and elimination diets in inflammatory bowel disease. Am J Clin Nutr. 1997;65:564-567.
10) Allen NE, Appleby PN, Davey GK,et al.The associations of diet with serum insulin-like growth factor I and its main binding proteins in 292 women meat-eaters vegetarians, and vegans. Cancer Epidemiol Biomarkers Prev. 2002;11(11):1441-1448.
11) Norat T, Dossus L, Rinaldi S, et al. Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women. Eur J Clin Nutr. 2007;61(1):91-98
12) USDA National Nutrient Database for Standard Reference: http://www.nal.usda.gov/fnic/foodcomp/search/.
13) Chan JM, Stampfer MJ, Ma J, Gann PH, Gaziano JM, Giovannucci E. Dairy products, calcium, and prostate cancer risk in the Physicians’ Health Study. Am J Clin Nutr. 2001;74:549-554.

Joseph Gonzales, R.D., is a dietician for The Cancer Project in Washington D.C.
He holds a Bachelor of Science in Nutrition from Bastyr University.