Prof.Dr.Hofi Site - Milk And Health

10 Great Reasons to Choose Milk Products

No other single food provides as much nutrition as a glass of milk. Milk is our number one source of calcium, phosphorus, riboflavin and vitamin D, and is among the top three sources of protein, vitamins A and B12, potassium, and zinc. The same is true for most milk products. This abundance of nutrients works together to benefit overall health. More than just a weapon against osteoporosis and dental cavities, milk products have been shown to help reduce the risk of developing kidney stones, hypertension, diabetes, PMS, certain cancers (e.g., colon, breast), gout and obesity in men and women.

Osteoporosis

Osteoporosis affects one in every four white women over age 50 and one in eight men that age — approximately 1.5 million Egyptians. That number could be cut in half if adequate calcium and vitamin D intakes were assured.¹ Adequate calcium maximizes peak bone mass achieved by the time we reach our twenties and minimizes age-related bone loss later in life.2 Children who avoid milk may fail to reach their genetic potential for peak bone mass, making them more vulnerable to osteoporotic fractures as adults.3 Unlike the short-term benefits of calcium supplements,4 dairy intake during childhood has demonstrated persistent, long-term benefits to bone.^5,6 In fact, among women aged 20 to 49 years, bone mineral content was significantly lower in those with low milk intake in childhood and adolescence. Women 50+ years who drank less than one serving of milk per week during childhood doubled their risk of hip fracture compared to those who drank at least one serving of milk per day.⁶ Studies have also shown that along with adequate calcium and vitamin D, higher intakes of protein are associated with significant gains in bone mineral density in elderly men and women.^7,8 In addition to calcium, milk provides protein, phosphorus, vitamins A and D, zinc and magnesium-bone-building nutrients that are important for life-long bone health.⁶

References:

1. Heaney RP. 1996. J Am Coll Nutr 15:575-578.

2. Cadogen J et al. 1997. Br Med J 315:1255-1260.

3. Black RE et al. 2002. Am J Clin Nutr 76:675-680.

4. Lee WTK et al. 1997. Acta Paediatr 86:570-576.

5. Bonjour J-P et al. 2001. Lancet 358:1208-1212.

6. Kalkwarf H et al. 2003. Am J Clin Nutr 77:257-265.

7. Dawson-Hughes B and Harris S. 2002. Am J Clin Nutr 75:773-779.

8. Promislow JHE et al. 2002. Am J Epidemiol 155:636-644.

Dental Health

Even kids know that calcium in milk helps build strong teeth, but few know that cheese is an important ally against tooth decay, helping to prevent both coronal and root caries.^1-3 Plaque bacteria that stick to the teeth use sugary foods to produce organic acids that attack the teeth, causing tooth-mineral loss. Dairy calcium (particularly in cheese) and milk protein help restore lost tooth mineral. The calcium and phosphate in cheese are absorbed into the plaque, helping to prevent cavities. Cheese also increases the secretion of saliva — not just while eating it but for a good five minutes thereafter-and alters its composition, neutralizing both plaque pH and acids and increasing the clearance of food from the mouth.¹ For maximum protection, cheese should be eaten by itself at the end of a meal. In addition, milk protein prevents bacteria from collecting in the mouth and modifies dental plaque, thereby reducing cavities.² What's more, dairy fat coats the teeth, decreasing the amount of fermentable carbohydrate retained in the mouth and preventing acid from penetrating the teeth.⁴
References:

1. Kashket S and DePaola DP. 2002. Nutr Reviews 60:97-103.

2. Papas AS et al. 1995. Am J Clin Nutr 61(suppl):417S-422S.

3. Jenkins GN and Hargreaves JA. 1989. Caries Res 23:159-164.

4. Jensen ME. 1999. Cariol 43:615-633.

Insulin Resistance Syndrome

Insulin resistance syndrome (IRS) is a combination of at least two interrelated conditions, including obesity, impaired glucose metabolism, hypertension, low HDL cholesterol and high triglyceride concentrations. Estimated to affect approximately 25% of our adult population, IRS interferes with the body's ability to control blood sugar, thereby increasing the risk of type 2 diabetes and cardiovascular disease. Because of their extra weight, overweight individuals are most vulnerable to IRS. The Coronary Artery Risk Development in Young Adults (CARDIA) Study followed 3,157 adults aged 18 to 30 years over a ten-year period. Overweight subjects (i.e., body mass index ≥ 25) who had less than 1 1/2 servings of milk products per day tripled their risk of developing IRS, compared to those who consumed at least five servings per day.¹ Each daily serving of milk or a milk product (regular or fat reduced) was associated with a 21% lower risk of IRS or its components.¹ This was independent of other lifestyle factors and dietary variables, sex, age and race. Moreover, contrary to established belief, eating more milk products did not increase LDL cholesterol, a major risk factor in heart disease, though not a component of IRS.¹ In the Bogalusa Heart Study, young adults (18-38 years) with no risk factors for IRS were found to consume significantly more low-fat dairy products than did those with three or more risk factors.² Milk, yogurt and cheese are foods with a very low glycemic index, compared to the reference standard glucose (GI=100).³References:

1. Pereira MA et al. 2002. JAMA 16:2081-2089.

2. Yoo S et al. 2004. Am J Clin Nutr 80:841-848.

3. Foster-Powell K et al. 2002. Am J Clin Nutr 76:5-56.

Hypertension

Approximately 25% of Egyptian adults are hypertensive and, therefore, at greater risk of heart disease and stroke. The Dietary Approaches to Stop Hypertension (DASH) study assessed the effects of dietary patterns on blood pressure and found that adults who consumed a diet high in fruits and vegetables (8 to 10 servings/day) had lower blood pressure than those who did not.¹ With the addition of about three servings of milk products, the blood pressure-lowering effect was doubled-enough to treat mild hypertension and prevent it in those with normal blood pressure. The DASH diet, as it is now called-rich in milk products, fruits and vegetables and low in fat-lowers blood pressure in men and women, regardless of age.¹ Reductions in blood pressure of the magnitude achieved by the DASH diet could translate into a 15% reduction in coronary heart disease and a 27% reduction in stroke.¹ The diet also lowers serum homocysteine levels, an independent risk factor for heart disease,² as well as total and LDL cholesterol.³ In their guidelines for the year 2000, the American Heart Association recommended the DASH diet for heart health.⁴

References:

1. Appel LJ et al. 1997. N Eng J Med 336:1117-1124.

2. Appel et al. 2000. Circulation 102:852-857.

3. Obarzanek E et al. 2001. Am J Clin Nutr 73:759-764.

4. Krause RM et al. 2000. Circulation 102:2284-2299.

Weight loss and management

Increased intake of milk products can help one lose weight where it counts-around the middle. Epidemiological studies suggest that, over time, adults^1-7 and children^8-12 who consume a low-calcium or low-dairy diet gain more weight and more body fat than those with higher dietary calcium intakes. Dietary calcium markedly accelerates the burning of fat for energy (lipolysis) and helps prevent the conversion of excess carbohydrate to fat (lipogenesis), resulting in less fat storage.¹³ In Dr. Zemel's studies of both mice and human subjects, dairy calcium and dairy products were substantially more effective than calcium supplements in reducing both body fat and body weight, particularly for those on a calorie-reduced diet.¹³ In a 24-week trial, 32 obese but otherwise healthy adults were randomized to diets different in milk product intake and designed to promote a one-pound (~1/2-kilogram) weight loss per week.⁵ Only those in the high dairy group (1,200 mg calcium including three servings of dairy product/day) had significant decreases in total body fat, trunk fat, and blood pressure, and an increase in lean muscle mass.⁵ In a second similarly designed trial, 105 overweight/obese adults on calorie-restricted diets were followed for 12 weeks. Individuals on the high-dairy diet (3 servings dairy, ~1,400 mg calcium/day)⁶ experienced an almost two-fold greater decrease in fat loss, trunk fat loss and waist circumference than those on the low-calcium (~600 mg/day) or high-calcium (~1,400 mg/day) diets.⁶ The high-dairy diet was associated with the greatest weight loss and the greatest increase in percentage of lean tissue. Summerbell and colleagues had similar findings: In their 16-week, randomized, controlled trial of three weight-reduction diets, outpatients on the 800-calorie milk and yogurt-only diet lost 11.2 kg (~25 lbs). Those on a standard 800-calorie, control diet lost less than 3 kg (~6 lbs) while those on a 1,300-calorie diet, consisting of milk and yogurt plus one other food, lost almost three times more: 8.2 kg (~18 lbs).¹⁴

References:

1. Pereira MA et al. 2002. JAMA 298:2081-2089.

2. Jacqmain M et al. 2003. Am J Clin Nutr 77:1448-1452.

3. Lin Y-C et al. 2000. J Am Coll Nutr 19:754-760.

4. Lovejoy JC et al. 2001. Am J Clin Nutr 74:90-95.

5. Zemel MB et al. 2004. Obesity Res 12:582-590.

6. Zemel MB et al. 2004. FASEB J 18(5 Pt II):A846 (abstract).

7. Loos RF et al. 2004. J Nutr 134:1772-1778.

8. Carruth BR and Skinner JD. 2001. Int J Obes Relat Metab Disord 25:559-566.

9. Skinner JD et al. 2003. J Am Diet Assoc 103:1626-1631.

10. Moore LL et al. 2004. Presentation: 44th Annual Conference on Cardiovascular Disease, Epidemiology and Prevention, March 4, 2004.

11. Novotny R et al. 2004. J Nutr 234:1905-1909.

12. Tanasecu M et al. 2000. J Nutr 130:1734-1742.

13. Zemel MB. 2003. J Nutr 133:252S-256S.

14. Summerbell CD et al. 1998. BMJ 317:1487-1489.

Kidney Stones

Contrary to popular opinion, high calcium intake does not increase the risk of developing kidney stones. In fact, the evidence is compelling that the opposite is true. While most stones are composed of calcium-oxalate, it is the oxalate-not the calcium — that is chiefly responsible for stone formation. Since dietary calcium binds with oxalate in the intestine thereby inhibiting its absorption, low calcium diets could actually increase the risk of stones. Studies have shown that increased consumption of calcium — rich milk products reduces the risk of kidney stones in both men¹ and women.² Calcium supplements have not demonstrated the same protection, perhaps because they are usually taken without food. Food is necessary if calcium is to bind with oxalate and prevent the formation of kidney stones.

References:

1. Curhan GC et al. 1993. N Eng J Med 328:833-838.

2. Curhan GC et al. 1997. Ann Intern Med 126:497-504.

Colon Cancer

The second most common cause of cancer death in the Western world, colon cancer owes more to environmental and lifestyle factors than to genetics. A pooled analysis of 10 prospective cohort studies in five countries has shown that higher consumption of milk and calcium is associated with a lower risk of colorectal cancer.¹ And it doesn't take that much milk. Together, these studies followed the dairy-eating habits of 534,536 individuals, among whom 4,992 incident cases of colorectal cancer were diagnosed between six and 16 years. The data showed that those who drank at least one glass of milk (250 mL) per day were 15% less likely to develop colorectal cancer than those who drank little or no (<70 mL/day) milk (p_trend <0.001).¹ Moreover, each 500 mL-per-day increase in milk intake (about two glasses) was associated with a 12% reduced rate of colorectal cancer risk. The inverse association between milk intake and colorectal cancer risk was limited to cancers of the distal colon and rectum,¹ cancers hypothesized to be related more to exogenous factors such as diet than cancers of the proximal colon. On the other hand, cheese and yogurt consumption had little impact, possibly because people ate much less of them.¹ The assessment of the independent effects of calcium and vitamin D intake showed that the relative risk was lowest (RR=0.74) for persons in the highest category of both total calcium and total vitamin D intake compared with the lowest category of intake for both nutrients.¹ A randomized trial of 803 individuals has shown that calcium supplementation and vitamin D status appear to act in synergy to reduce the risk of colorectal adenoma recurrence.²

References:

1. Cho E et al. 2004. J Natl Cancer Inst 96:1015-1022.

2. Grau MV et al. 2003. J Natl Cancer Inst 95:1765-1771.

Breast Cancer

Finnish researchers were among the first to suggest that milk drinkers have a significantly lower risk of developing breast cancer.¹ More recently, in the Norwegian Women and Cancer Study of 48,844 premenopausal women, those who drank milk during both childhood and adulthood had a substantially reduced risk of breast cancer.² And the more milk, the better. Compared to those who drank little or no milk, moderate milk drinkers were shown to have one-quarter the risk of breast cancer, while heavy milk drinkers had half.² These findings may be due in part to the conjugated linoleic acid (CLA) content of milk. CLA, a class of fatty acids found mainly in dairy fat, slows the development and growth of mammary tumours in animals.³ And it appears to have similar effects in women. Postmenopausal women with the highest intake of CLA-rich foods, particularly cheese, had higher levels of CLA in their blood and, more important, at least a 70% lower risk of breast cancer.⁴ Questions about the impact of milk products on breast cancer risk remain, in part because the assessment of dietary factors in relation to cancer risk is notoriously difficult and subject to bias.⁵

References:

1. Knekt P et al. 1996. Br J Cancer 73:687-691.

2. Hjartåker A et al. 2001. Int J Cancer 93:888-893.

3. Ip C et al. 1999. J Nutr 129:2135-2142.

4. Aro A et al. 2000. Nutr Cancer 38:151-157.

5. Moorman PG and Tern PD. 2004. Am J Clin Nutr 80:5-14.

PMS

Calcium-rich milk products are the most effective dietary approach to alleviating the majority of mood and physical symptoms associated with premenstrual syndrome (PMS). Women with PMS appear to suffer from abnormalities of calcium metabolism, suggesting that PMS is actually a manifestation of calcium deficiency that occurs following the rise of estrogen during the menstrual cycle. In intervention studies, women with PMS in the high-calcium groups (1,000 - 1,300 mg), either from supplements or milk products, experienced significant improvements in mood, behaviour, pain and bloating during the menstrual cycle.^1,2 What's more, at least two studies indicate that women with PMS are prone to lower bone mass or increased fracture, confirming the link between PMS and low calcium intake.^1,2

References:

1. Thys-Jacobs S. 2000. J Am Coll Nutr 19:220-227.

2. Bendich A. 2000. J Am Coll Nutr 19:3-12.

Gout

Affecting as many as 3.4 million men in the U.S., gout is the most common form of inflammatory arthritis in men. Sufferers are generally advised to avoid purine-rich foods such as meat, seafood, purine-rich vegetables, and animal protein. But a recent study of 730 men with confirmed gout suggests that not all animal proteins are created equal. Whereas higher levels of meat and seafood were associated with an increased risk of gout, a higher level of dairy intake had the opposite effect.¹ Moreover, the incidence of gout decreased with increasing intake of low-fat dairy products. Risk of gout was almost half among men who drank two or more (240 mL, 8 oz) glasses of skim milk per day, as compared with those who drank less than one glass per month (p_trend <0.001).1 Similar reductions in risk applied to dairy-protein intake, but not other animal proteins.¹ Dairy products are low in purine. That's likely why milk proteins have been shown to reduce serum uric acid levels in healthy individuals. Evidence of this effect has also been demonstrated conversely by a four-week randomized clinical trial in which a dairy-free diet induced a significant increase in uric acid levels.² The consumption of dairy products- particularly those low in fat-and dairy protein is strongly associated with the reduced risk of gout in men 40 years and older. Moderate intakes of purine-rich vegetables and protein are not.

References:

1. Choi HK et al. 2004. N Engl J Med 350:1093-1103.

2. Ghadirian P et al. 1995. Eur J Epidemiol 11:275-281.