Lactose is the main carbohydrate in milk. Many nutritional supplements utilize milk derived ingredients as primary sources of protein because of their high biological value, and consequently may also contain some lactose. Milk derived products are also advantageous in nutritional supplements since they provide calcium and other vitamins and minerals. (View our Lactose Free Products)
The amount of lactose contributed by a milk protein will depend on the amount and type used. The lactose content can range from as little as 1% in caseinates to 55% in nonfat dry milk. Whey can have a wide range of lactose content, 4%-50%, with whey protein isolates having less than 5% lactose and many whey protein concentrates used in our products contain less than 10% lactose as they are very high in protein.
Lactose is less soluble than other sugars and remains in the intestines long enough to encourage the growth of desirable bacteria which are useful in the synthesis of some B-complex vitamins. Lactose can also enhance the absorption and utilization of calcium; it is therefore advantageous that milk, an outstanding source of calcium, contains lactose.
LACTOSE INTOLERANCE is the inability to digest lactose due to a deficiency of the enzyme lactase. When undigested lactose is in the gastrointestinal tract it attracts water causing fullness, discomfort, cramping, nausea and diarrhea. In the intestines undigested lactose is utilized by normal intestinal bacteria which multiply and produce irritating acid and gas, further contributing to discomfort and diarrhea.
The loss of lactase activity in adults is most frequently due to a genetic factor common in individuals of non-European origin, except in areas where there was also a tradition of dairy farming. It is thought that in populations where milk was a common food there was a genetic adaptation favoring lactose absorption. It has been estimated that worldwide occurrence of lactase deficiency in adults is near 70%. In the United States the incidence of lactose intolerance is approximately 6-11% among those of European ancestry. The occurrence is higher in other cultural segments of the population.
The development of symptoms appears to depend on the amount of lactose ingested and can be influenced by the nature of other foods consumed. Many lactose intolerant individuals can consume some lactose (less than 10-12 grams) without side effects, or can tolerate higher amounts with a meal or by using commercially available aids to digest lactose. Individuals who do not consume milk products may have a dietary deficiency in calcium and may need alternate sources of dietary calcium.
It should be pointed out that lactose intolerance is not the same as a milk allergy. A milk allergy is caused by an immune reaction to the protein in milk. Individuals with a milk allergy need to use products with alternative protein sources such as egg or soy protein.
Suarez RL, Savaiano DA, Levitt MD. A comparison of symptoms after the consumption of milk or lactose hydrolyzed milk by people with self-reported severe lactose intolerance. New England Journal of Medicine, 333(1):1-4 1995.
Diet and Health. Committee on Diet and Health, Food and Nutrition Board, Commission on Life Sciences, National Research Council; National Academy Press, Washington, DC; 1989.
Whitney EN; Hamilton EMN; Rolfes SR. Understanding Nutrition, fifth edition, West Publishing Company, St Paul, MN 1990.
Savaiano DA; Levitt MD. Milk intolerance and microbe-containing dairy foods. Journal of Dairy Science, 70(2):397-406 1987.
Houts, SS. Lactose intolerance. Food Technology, 42(3):110-113 1988.
Dairy Council Digest, National Dairy Council, Rosemont, IL, Mar/Apr 1994.