Health Benefits of Dairy Foods: Heart Disease and Stroke

Dairy consumption does not elevate heart attack risk

Dairy products can be high in harmful saturated fat but not necessarily in risk to the heart. A newly published analysis of thousands of adults in Costa Rica found that their levels of dairy consumption had nothing to do statistically with their risk of a heart attack.

“Things like milk and cheese are very complex substances,” said Stella Aslibekyan, a community health graduate student at Brown University and the lead author of the study, published in the journal Nutrition, Metabolism and Cardiovascular Diseases. “We looked at [heart attack risk and] dairy products in their entirety and then looked at separate components of those dairy products, including fats, and it turns out that the results are null. Perhaps the evidence is not there.”

Rather than suggesting that the saturated fats in dairy products are harmless, Aslibekyan and co-author Ana Baylin, an adjunct assistant professor of community health at Brown, hypothesize that other nutrients in dairy products are protective against heart disease, for all but perhaps the highest dairy consumption quintile in their study. The potentially beneficial nutrients include calcium, vitamin D, potassium, magnesium and conjugated linoleic acid (CLA).

To conduct the study, Aslibekyan and Baylin analyzed data on 3,630 middle-aged Costa Rican men and women who participated in an epidemiological study between 1994 and 2004 by co-author Hannia Campos of the Harvard School of Public Health.

They split the study population between two equal groups: 1,815 “cases” who had non-fatal heart attacks and 1,815 comparable “controls” who did not. The researchers looked not only at the subjects’ self-reported dairy intake, but also at measurements of dairy fat biomarkers, namely 15:0 and 17:0, in their bodies.

What they found is that the dairy intake of people who had heart attacks was not statistically different than the intake of people who did not. After breaking people into quintiles, based on their dairy consumption amount, there was no significant linear relationship between consumption and heart risk, even among the most voracious consumers. The highest consumption quintile consumed an average of 593 grams of dairy foods a day.

When the researchers controlled for such risk factors as smoking, waist-to-hip ratio, alcohol intake, and physical activity, the lack of a statistically significant association between dairy intake and heart attack risk remained. They also tracked and adjusted the data for levels of CLA and calcium and found they may have a protective effect. Protective effects lessened in the highest quintile, however.

Baylin likened the nutritional complexity of dairy products to that of eggs, which were once a source of intense consumer concern because of their cholesterol content, but are now viewed in a more complex way because they, too, have seemingly protective nutrients.

“The message is that it is important to look at the net effect of whole foods and dietary patterns and not only isolated nutrients” Baylin said.

Dairy consumption linked to lower blood pressure and cardiovascular disease risk

Globally, cardiovascular disease (CVD) claims 17 million lives each year, while complications from high blood pressure take an additional 9.4 million.¹ New research presented by international scientists at the 12th Euro Fed Lipid Congress in Montpellier, France on September 15, 2014, suggests that milk consumption and dairy may play a beneficial role.

At the Milk and Dairy Products in Human Health session, the association between milk and risk for hypertension and CVD was examined by Dr. Sabita S. Soedamah-Muthu from Wageningen University in the Netherlands. Dr. Soedamah-Muthu explained that, based on nine studies with 57,256 individuals and 15,367 cases of hypertension, the analysis revealed that as total dairy, low-fat dairy and milk (just over two cups a day) consumption increased, the risk for high blood pressure decreased. Milk intake was not statistically significantly associated with risk of coronary heart disease, stroke and total mortality.

"These meta-analyses indicate that there is a link between increasing the number of glasses of milk a day and a lower incidence of hypertension," explained Dr. Soedamah-Muthu. These findings are further supported by a clinical trial by Daniel R. Machin, et. al. published in the American Journal of Clinical Nutrition in May 2014 that showed the addition of four servings of nonfat dairy per day to a routine diet lowered blood pressure in middle-aged and older adults.

In addition to reviewing the role of dairy and heart health, international experts presented data evaluating the effects of dairy products and dairy fat on chronic disease risk factors, such as cholesterol biomarkers, body fat accumulation and weight gain. New research about milk fat and associated fat-soluble nutrients in infant formula to benefit brain development and to enhance elderly nutrition suggest an untapped nutritional value of dairy food components.

"The results of this diverse session lay the groundwork for future investigations into the overall impact dairy may have on public health," notes Dr. Cindy Schweitzer, PhD, CFS, Technical Director, Global Dairy Platform. "It appears that dairy's nutrient-rich package may have a positive impact on health, development and performance in more ways than previously expected."

Cheese May be Good For You

A new piece in the 'French paradox' puzzle -- cheese metabolism

Figuring out why the French have low cardiovascular disease rates despite a diet high in saturated fats has spurred research and many theories to account for this phenomenon known as the "French paradox." Most explanations focus on wine and lifestyle, but a key role could belong to another French staple: cheese. The evidence, say scientists in ACS' Journal of Agricultural and Food Chemistry, is in cheese metabolism.

Hanne Bertram and colleagues note that recent research on some dairy products' positive effects on health has cast doubt on the once-firm rule that saturated fats are bad for our hearts. For example, one study found that cheese reduced "bad" cholesterol when compared to butter with the same fat content, suggesting that high cheese consumption could help explain the French paradox. To further investigate this possible explanation, Bertram's team looked into how cheese gets digested.

The researchers compared urine and fecal samples from 15 healthy men whose diets either contained cheese or milk, or who ate a control diet with butter but no other dairy products. They found that those who consumed cheese had higher fecal levels of butyrate, a compound produced by gut bacteria. Elevated butyrate levels were linked to a reduction in cholesterol. Their results, they say, suggest a role for gut microbes and further shore up the connection between cheese and the French paradox.

Consuming Low-Fat Dairy Food May Reduce Your Risk Of Stroke

If you eat low-fat dairy foods, you may be reducing your risk of stroke.

In a Swedish study published in the American Heart Association's journal Stroke, people who drank low-fat milk and ate low-fat yogurt and cheese had a lower risk of stroke compared to those who consumed full-fat dairy foods.

Among 74,961 adults 45 to 83 years old, those who ate low-fat dairy foods had a 12 percent lower risk of stroke and a 13 percent lower risk of ischemic stroke than those who ate high-fat dairy foods.

Participants were free of heart disease, stroke and cancer at the start of the study. All completed a 96-item food and beverage questionnaire to determine dietary habits. Food and drink consumption frequency was divided into eight categories, ranging from never to four servings per day.

During the 10-year follow-up, 4,089 strokes occurred (1,680 in women and 2,409 in men): 3,159 ischemic, 583 hemorrhagic and 347 unspecified strokes.

"This is the largest study to date to examine the association between consumption of total, low-fat, full-fat and specific dairy foods and the risk of stroke in adult men and women," said Susanna Larsson, Ph.D., the study's first author and associate professor of epidemiology in the Division of Nutritional Epidemiology, National Institute of Environmental Medicine, at the Karolinska Institute in Stockholm, Sweden.

"From a public health perspective, if people consume more low-fat dairy foods rather than high-fat dairy foods, they will benefit from a reduced risk of stroke and other positive health outcomes."

The benefits of low-fat dairy foods are likely due to the vitamins and minerals they contain: calcium, potassium, magnesium and vitamin D.

"It is possible that vitamin D in low-fat dairy foods may explain, in part, the observed lowered risk of stroke in this study because of its potential effect on blood pressure," Larsson said.

Low-fat dairy food is one part of the Dietary Approaches to Stop Hypertension (DASH) Diet, which reduces blood pressure. High blood pressure is a major risk factor for stroke.

Northern Europeans and North Americans traditionally consume much more dairy foods than other global populations. So switching to low-fat dairy products could impact stroke risk for millions of people, Larsson said. More research on the link between low-fat dairy consumption and risk of stroke is needed, Larsson said.

New study suggests fat-free milk may offer protection against hypertension -- a rising risk for women in this country

Women who drank more fat free milk and had higher intakes of calcium and vitamin D from foods, and not supplements, tended to have a lower risk for developing hypertension or high blood pressure, according to a new study published in the American Heart Association journal, Hypertension.

After examining the diets of nearly 30,000 middle-aged and older women, Harvard researchers found that women who consumed more low-fat milk and milk products and had diets higher in calcium and vitamin D from foods were better protected against high blood pressure. When the researchers investigated the benefits of milk specifically, they found women who drank two or more servings of fat free milk each day reduced their risk for high blood pressure by up to10 percent compared to those who drank fat free milk less than once a month. The same was not found for higher fat milk and milk products or calcium and vitamin D supplement users.

One in three American adults has high blood pressure, and an increasing number of women are living with undiagnosed hypertension, according to a second study published in the journal Circulation. The last decade has seen significant increases in uncontrolled high blood pressure for women across the nation, a condition that puts them at serious risk for cardiovascular disease, stroke and even kidney failure.

Yet despite a vast body of research linking diet changes to blood pressure control, most Americans are still missing the mark on their diets. According to new research published in the Archives of Internal Medicine, Americans are ignoring the DASH (Dietary Approaches to Stop Hypertension) Diet, the therapeutic eating plan recommended by the National Heart Lung and Blood Institute that emphasizes low-fat dairy, fruits and vegetables to help reduce blood pressure levels.