Every nutritionist knows (or should know) that a DASH eating plan is incredibly effective for helping patients to lower their blood pressure. A staple on the plan are low-fat or non-fat dairy foods (think 2 percent or skim milk versus whole milk) because they are considered more heart healthy than full-fat dairy, but the results of a 16-year prospective study just published in the European Journal of Clinical Nutritianare suggesting otherwise.
Bonthuis et al are calling for more studies to assess whether or not full-fat dairy may have more cardioprotective benefits than low-fat or nonfat dairy (1). The researchers found that among more than 1,500 adult Australians regularly consuming dairy products, those with highest consumption of full-fat dairy had reduced mortality when compared with those who ate low-fat dairy (1). This was after adjusting for possible confounders such as calcium and vitamin D. Most of the deaths of the participants in the study were related to cardiovascular disease and cancer (1).
The study overall confirms that dairy deserves to continue to be part of DASH and a previously published cohort from Australia that dairy could lower all-cause mortality (2). The study also questions recommendations of avoiding full-fat dairy for long-term protection against chronic disease.
Where did the recommendation to go for the low-fat dairy come from anyway?
The recommendation appeared because of studies that found that low-fat dairy was associated with lower blood pressure, but that full-fat dairy was not. Somewhat recently, the National Heart, Lung, and Blood Institute Family Heart Study in 2006 found an inverse association between prevalent hypertension and consumption of a diet containing dairy low in saturated fat (3).
Given the newest Australian findings, the dairy and blood pressure relationship may be dependent on the fatty acid make-up of the dairy. Could there be something about Australian dairy sources that are cardioprotective? The researchers no doubt must have this data and I imagine less saturated fat and more omega-3s would be involved in their results.
So, don't go switching to whole milk yet. If you like that full-fat flavor, then consider drinking omega-3-fortified dairy.
Just last month in March, a double-blind, cross-over study confirmed that omega-3-fortified dairy foods improved lipid profiles decreasing cardiovascular risk factors (4). The dairy improved omega-3 index, lowered total cholesterol, lowered LDL cholesterol, and lowered triglycerides significantly (4).
Once again, the fact of the matter is that it is the amount of omega-3s in any food that may truly determine how cardioprotective the food really is, as well as its lack of saturated fat and trans fat. Milk is no exception to this nutritional rule.
1. Bonthuis M, Hughes MC, Ibiebele TI, Green AC, van der Pols JC. Dairy consumption and patterns of mortality of Australian adults. Eur J Clin Nutr. 2010 Apr 7. [Epub ahead of print] Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/20372173.
2. van der Pols JC, Gunnell D, Williams GM, Holly JM, Bain C, Martin RM. Childhood dairy and calcium intake and cardiovascular mortality in adulthood: 65-year follow-up of the Boyd Orr cohort. Heart. 2009 Oct;95(19):1600-6. Epub 2009 Jul 29.
3. Djoussé L, Pankow JS, Hunt SC, Heiss G, Province MA, Kabagambe EK, Ellison RC. Influence of saturated fat and linolenic acid on the association between intake of dairy products and blood pressure. Hypertension. 2006;48:335.
4. Dawczynski C, Marin L, Wagneer A, Jahreis G. n-3 LC-PUFA-enriched dairy products are able to reduce cardiovascular risk factors: A double-blind, cross-over study. Clinical Nutrition. Mar 19. [Epub ahead of print]