HOME
Dairy for children 'extends life'
Calcium, dairy rich diets in childhood may lower mortality
By Caroline Price
28 July 2009
Eur Heart J 2009: Not yet available online
MedWire News: Children in the 1930s whose diets were high in calcium and dairy products had reduced all-cause mortality, and those with high-calcium diets reduced stroke mortality, in adulthood, reveals a UK study upcoming in the journal Heart.
The beneficial effects were seen at estimated intake levels similar to those currently recommended in children, note the authors.
"The practice of giving extra milk to school children to encourage growth was common in Europe in the 20th century and milk consumption by children is still encouraged in many European countries world wide," explain Joileke van der Pols (Queensland Institute of Medical Research, Brisbane, Australia) and colleagues.
"Yet concern has been expressed about the possible long-term health effects of dairy consumption in relation to cancer and cardiovascular disease risk, and safe intake levels are being debated."
To investigate, the team conducted at 65-year follow-up study of 4999 children in England and Scotland who participated between 1937 and 1939 in a study of family food consumption. Data in the original survey – the Carnegie ("Boyd Orr") survey – were obtained using 7-day household food inventories. Per capita food and nutrient intake was estimated by dividing the total daily intake by the number of household members.
The researchers were able to follow up 4374 of the original children between 1948 and 2005. A total of 1468 (34%) died, including 378 due to coronary heart disease and 121 due to stroke.
They found no strong evidence for an association between dairy products and coronary heart disease or stroke mortality.
But calcium intake was inversely associated with stroke mortality, with a multivariable adjusted hazard ratio (HR) of 0.41 for the highest (683-2198 mg per day) versus lowest (150-397 mg per day) calcium intake group (p for trend=0.04).
Similarly, all-cause mortality was lowest in those with the highest family dairy intake (mean 471 g per day) group, with an adjusted HR of 0.77 versus those in the lowest (mean 89 g per day; p for trend=0.04).
All-cause mortality was also inversely associated with calcium intake, at a HR of 0.77 for the highest versus lowest intake group (p for trend=0.05).
Van der Pols and team note that, although not significantly associated with intake of milk, calcium, or dairy products, "for all three of these intercorrelated aspects of diet, coronary heart disease mortality was lowest in the highest intake group."
"In conclusion, this study showed that a family diet in childhood relatively high in calcium is associated with reduced stroke mortality and that a childhood diet high in dairy or calcium is inversely associated with total mortality in adulthood," write the authors.
The study above confirms research undertaken by the Universities of Reading, Cardiff and Bristol, published last year, which also found that drinking milk can lessen the chances of dying from illnesses such as coronary heart disease (CHD) and stroke by up to 15-20 %.
In recent times milk has often been portrayed by the media as an unhealthy food. This study, led by Professor Peter Elwood (Cardiff University) together with Professor Ian Givens from the University of Reading's Food Chain and Health Research Theme, aimed to establish whether the health benefits of drinking milk outweigh any dangers that lie in its consumption.
Importantly, this is the first time that disease risk associated with drinking milk has been looked at in relation to the number of deaths which the diseases are responsible for.
The review brought together published evidence from 324 studies of milk consumption as predictors of coronary heart disease (CHD), stroke and, diabetes. Data on milk consumption and cancer were based on the recent World Cancer Research Fund report. The outcomes were then compared with current death rates from these diseases.
Professor Givens explained: "While growth and bone health are of great importance to health and function, it is the effects of milk and dairy consumption on chronic disease that are of the greatest relevance to reduced morbidity and survival. Our review made it possible to assess overall whether increased milk consumption provides a survival advantage or not. We believe it does.
"Our findings clearly show that when the numbers of deaths from CHD, stroke and colo-rectal cancer were taken into account, there is strong evidence of an overall reduction in the risk of dying from these chronic diseases due to milk consumption. We certainly found no evidence that drinking milk might increase the risk of developing any condition, with the exception of prostate cancer. Put together, there is convincing overall evidence that milk consumption is associated with an increase in survival in Western communities."
The reviewers also believe that increased milk consumption is likely to reduce health care costs substantially due to reduced chronic disease and associated morbidity.
"There is an urgent need to understand the mechanisms involved and for focused studies to confirm the epidemiological evidence since this topic has major implications for the agri-food industry," added Professor Givens.
Elwood PC, Givens DI, Beswick AD. The Survival Advantage of Milk and Dairy Consumption: an Overview of Evidence from Cohort Studies of Vascular Diseases, Diabetes and Cancer. J Am Coll Nutr 2008; 27: 723S-734S. Read the abstract here
Comments by health professionals
Joanne Murphy of The Stroke Association said of the later study: "This is an interesting study, but we need to take a further look to really assess the benefits of milk in reducing the chances of dying from stroke.
"In the meantime, we advise parents to opt for a diet rich in fruit and vegetables and low in saturated fat and salt for the overall health of their children."
June Davison, cardiac nurse for the British Heart Foundation said: "It is important to include dairy as part of a balanced diet from the early years.
"However, older children and adults should consume low-fat dairy products such as semi-skimmed, 1% or skimmed milk and low-fat yogurts, which will help keep saturated fat intake low to help protect the heart."
Studies investigating a link between cancer and dairy products have not given clear results. Some research shows an increase in the risk of developing cancer, and some shows a decrease.
And, in its report on the later study, the BBC's journalist wrote "Despite dairy containing artery furring fat and cholesterol, high consumption did not raise the heart disease risk."
MY COMMENT
These comments by professionals show the levels of ignorance which are now endemic in the 'health' industry. When I was at school in the 1940s and '50s, were given a half pint of full cream milk to drink each day. This was because of research before WWII which demonstrated that increased consumption of milk was beneficial to health.
But it was full-cream milk; today's children would be given semi-skim or skim milk — and that would be disastrous. Low-fat dairy has been shown to increase cancer risk, while full-fat dairy reduces it.
And what the BBC's correspondent should have said, of course, was: "Because full-fat dairy contains saturated fat and cholesterol, high consumption does not raise the heart disease risk." Because, although 'everybody knows' that saturated fats and dietary cholesterol 'clog arteries' and cause heart disease, such ideas have been shown to be false many times. On the contrary, studies have shown that arterial plaque is primarily composed of unsaturated fats, particularly polyunsaturated ones, and not the saturated fats.1
Saturated fats are actually beneficial in heart disease: "These effects include the paradox that a high-saturated fat diet is associated with diminished coronary artery disease progression."2 "a greater saturated fat intake is associated with less progression of coronary atherosclerosis"3 "[high saturated fat very low carbohydrate diets] are more effective in improving triacylglycerols, HDL-C, fasting and post prandial glucose and insulin concentrations."4
And the conversion of n-3 alpha-linolenic acid to EPA and DHA (which also helps the heart) is enhanced when the diet contains saturated fat, and hindered when there is omega-6 vegetable margarines and oils in the diet.5
In fact, what these studies are doing is confirming the healthy dietary advice, first proposed by Sir John Boyd Orr in the 1930s, and showing the harm that the current 'healthy eating' propaganda is doing.
References
1. Felton CV, et al. Dietary polyunsaturated fatty acids and composition of human aortic plaques. Lancet 1994; 344:1195-96.
2. Knopp RH, Retzlaff BM. Saturated fat prevents coronary artery disease? An American Paradox. Am J Clin Nutr 2004; 80:1102-3.
3. Mozaffarian D, et al. Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. Am J Clin Nutr 2004; 80: 1175-84.
4. Noakes M, et al. Comparison of isocaloric very low carbohydrate/high saturated fat and high carbohydrate/low saturated fat diets on body composition and cardiovascular risk. Nutr Metab 2006; 3:7.
5. Gerster H. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? Int J Vitam Nutr Res 1998; 68: 159-73
Last updated 29 July 2009
Related Articles
- Begin at the Beginning: The Best Diet for Healthy Children.
- Unlimited calorie, low-carb diet better and healthier for obese children
- Low cholesterol and antisocial behaviour in children
- Expectant mother's low cholesterol damages babies
