(US) Lactose maldigestion and calcium from dairy products, excellent letter in American Journal of Clinical Nutrition

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(US) Lactose maldigestion and calcium from dairy products,

excellent letter in American Journal of Clinical Nutrition

 

Lactose maldigestion and calcium from dairy products

 

http://www.ajcn.org/cgi/content/full/70/2/301A

 

 

links milk to prostate cancer and heart disease, says milk doesn't stave off

osteoporosis, concludes with:

 

American Journal of Clinical Nutrition, Vol. 70, No. 2, 301A-302, August

1999

© 1999 American Society for Clinical Nutrition

 

Letters to the Editor

Lactose maldigestion and calcium from dairy products

William B Grant

12 Sir Francis Wyatt Place Newport News, VA 23606-3660 E-mail:

wbgrant

 

Dear Sir:

 

The recent publication of a paper in this Journal suggesting that lactose

maldigestion should not be considered an impediment to consuming dairy

products to obtain dietary calcium (1), which was

sponsored by the National Dairy Council, may mislead the readers. First,

dairy products may not be a good source of calcium for reasons other than

lactose intolerance. A recent report from the

Nurses' Health Study, which included 121701 women aged 30­55 y at

enrollment in 1976, concluded that the cohort study data do not support the

hypothesis that a high consumption of milk or

other food sources of calcium by adult women protects against hip or

forearm fractures (2).

 

To examine the link between milk and osteoporosis further, an ecologic

approach was used to study hip fracture incidence rates for the white and

total populations from 9 countries (3). The data for

Finnish women were omitted because they were both an outlier with respect

to women from other countries and inconsistent with rates of hip fracture

for the Finnish men. As shown in Table 1,

dietary milk and its components, especially milk protein, have a much

higher statistical association with hip fracture incidence than do other

likely factors such as fat, protein, and sweeteners (4).

When linear regressions were run for milk protein, the r value for women

was 0.800 (P = 0.005) and for men was 0.593 (P = 0.054). What the

statistical results show is that living in countries with

a high dairy consumption is a risk factor for osteoporosis. They do not

necessarily imply that consumption of dairy products causes osteoporosis;

however, they do suggest that further investigations

be conducted to determine why the associations are so high.

 

In addition, the annual hip-fracture rate of black females in California

was 43% that of white females (219 compared with 559 cases/100000 persons)

(3), whereas the hip-fracture rate of black

females in Washington, DC, was 51% that of white females (118.8 compared

with 231.8 cases/100000 persons) (5, 6). African Americans are generally

lactose intolerant and have lower milk

consumption rates than do white Americans. Perhaps their diet, genetic

makeup, or both lead to strong bones and therefore dairy products or large

amounts of dietary calcium are not as important as

they are for whites.

 

Other common chronic diseases are now linked to calcium and milk

consumption. Lactose from unfermented dairy products such as milk and

yogurt has the highest association with ischemic heart

disease of any dietary macronutrient for men of all ages and postmenopausal

women (7­9). A possible mechanism is the metabolism of lactose into

triacylglycerol and its incorporation into VLDL

cholesterol. In addition, milk and calcium intakes have been found in

cohort studies in 5 countries to be the highest risk factors for prostate

cancer (10). The proposed mechanism is a reduction in

circulating vitamin D by calcium because vitamin D is involved in the

incorporation of calcium into bone (10). Vitamin D has been shown to kill

prostate cancer cells in vitro (11).

 

Thus, there are many good reasons not to consume dairy products. Those

concerned about osteoporosis, which has a complex etiology, should review

the report by Brown (5), which delves far

beyond the relation between osteoporosis and calcium intakes into such

other factors as the dietary acid-alkaline balance, trace minerals,

exercise, and exposure to sunlight.

 

REFERENCES

 

1.Suarez FL, Adshead J, Furne JK, Levitt MD. Lactose maldigestion is

not an impediment to the intake of 1500 mg calcium daily as dairy products.

Am J Clin Nutr

1998;68:1118­22.[Abstract]

2.Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary

calcium, and bone fractures in women: a 12-year prospective study. Am J

Public Health 1997;87:992­7.[Medline]

3.Maggi S, Kelsey JL, Litvak J, Hayes SP. Incidence of hip fractures in

the elderly. A cross-national analysis. Osteoporos Int

1991;1:232­41.[Medline]

4.Food and Agriculture Organization. Food balance sheets. Rome: FAO,

1991.

5.Brown SE. Better bones, better body. New Canaan, CT: Keats

Publishing, Inc, 1996.

6.Melton L. Epidemiology of fractures, osteoporosis etiology, diagnosis

and management. In: Riggs B, Melton L, eds. New York: Raven Press,

1988:133­54.

7.Artaud-Wild SM, Connor SL, Sexton G, et al. Differences in coronary

mortality can be explained by differences in cholesterol and saturated fat

intakes in 40 countries but not in France and

Finland: a paradox. Circulation 1993;88:2771­9.[Abstract]

8.Segall JJ. Epidemiological evidence for the link between dietary

lactose and atherosclerosis. In: Colaco C, ed. The glycation hypothesis of

atherosclerosis. Austin, TX: Landes Bioscience,

1997:185­209.

9.Grant WB. Milk and other dietary influences on coronary heart

disease. Altern Med Rev 1998;3:281­94.[Medline]

10.Grant WB. An ecologic study of dietary links to prostate cancer.

Altern Med Rev 1999;4:162­9.[Medline]

11.Schwartz GG, Hill CC, Oeler TA, Becich MJ, Bahnson RR.

1,25-Dihydroxy-16-ene-23-yne-vitamin D3 and prostate cancer cell

proliferation in vivo. Urology 1995;46:365­9.[Medline]

 

 

 

 

 

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