Dietary pattern, not type, influences heart health, weight management

BOSTON — Certain dietary patterns receive attention for their ability to improve cardiovascular health, symptoms of metabolic syndrome and obesity, but the best diet choice may simply be the one a patient can stick with, according to a presenter at the Cardiometabolic Health Congress.

“There have been many studies that show diet type is not a factor in weight loss,” Frank M. Sacks, MD, professor of cardiovascular disease prevention at Harvard School of Public Health and a physician at Brigham and Women’s Hospital, said during a presentation on the science behind heart health and weight management. “It’s how much you eat and how much you exercise. Searching for that perfect or ideal diet is a fruitless task at this point. I advocate dietary patterns because they can be taught, rather than [focusing on] nutrients.”

Frank M. Sacks

Sacks outlined several popular dietary trends, noting their impact on heart health and weight loss.

The Mediterranean option

The make-up of the traditional Mediterranean diet can vary depending on the specific Mediterranean region, Sacks said. For example, in Italy fats make up 25% of the diet, but in Greece about 43%. The diet, which relies on olive oil as a principal source of fat, also incorporates cheese, yogurt, fish, poultry and only rarely, red meat, while wine is often consumed with meals.

In study after study, the Mediterranean diet has been associated with a reduction in cardiovascular events and cancer, Sacks said.

“To summarize, PREDIMED [study] and other studies of the Mediterranean diet have been shown to prevent cardiovascular disease, prevent diabetes, improve cholesterol, improve cognition, lower symptoms of depression, [provide] long-term efficacy for weight loss and improve sleep and sexual function,” Sacks said. “So, it sounds too good to be true, but all of these risk factors can be mechanistically linked to the changes in the Mediterranean diet. We certainly need to see more such studies.”

The Paleo diet

The Paleo diet is based on foods presumed to be eaten by early humans. According to anthropologists, a hallmark of the Paleolithic diet is its diversity among locales, Sacks said.

“In some locales, they [ate] quite a lot of carbohydrates,” Sacks said. “Starches from wild grains, grasses, beans, seeds, tubers … and in other areas, fruit was a major source, greater than 50% in some areas, and animal food was minor.”

Insects, such as termites, were a very prominent food source in some locales, such as Africa; while in Europe, tortoises and turtles were an important food source, Sacks said. When large mammal populations, such as wild horses, deer and donkeys, experienced population crashes, late Paleolithic humans shifted intake from large mammals to small mammals, such as hares and other species, birds, fish and plants, Sacks said.

“The concept that we, as humans, were genetically adapted to eating big mammals is just wrong,” Sacks said. “How about grains and flour? Perish the thought — grains and flour in a Paleo diet. But it was a part of the diet in some areas. There was extensive foraging and processing of wild plants, and highly specialized tools to separate the edible parts of plants.”

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The DASH diet

The Dietary Approaches to Stop Hypertension method, commonly known as the DASH diet, emphasizes fruits, vegetables and high-protein foods, including beans, whole grains, nuts, low-fat dairy, fish, poultry and unsaturated oils. The diet also calls for limiting carbohydrates, saturated fats, red meat, sweets and sugar-sweetened beverages, as well as decreasing sodium intake.

The DASH diet has been shown to reduce blood pressure and risk for cardiovascular events, Sacks said.

“In just 1 month of low sodium and the DASH diet, blood pressure dropped from levels [seen] at age 60 [years] to levels around age 30 [years],” Sacks said. “So, the DASH diet and low sodium abolishes 30 years of blood pressure aging. At least that’s the implication.”

Fats and oils

All fats, when they replace carbohydrates, lower blood triglycerides, with polyunsaturated fats having the greatest effect, Sacks said.

“Now, with saturated fat and heart disease, the replacement matters tremendously,” Sacks said. “This is where a bit of the controversy is … but this is a somewhat bogus controversy, because it is impossible to answer the question, ‘Is saturated fat good or bad?’ It’s a meaningless question. What you have to ask is, ‘Is saturated fat, compared to something else, good or bad?’ Because saturated fat produces calories in our diet.”

Carbohydrate lessons

It is important to remember that some carbohydrates can be beneficial, Sacks said.

“I’m not here to bash carbohydrates … because some foods containing carbohydrates are very beneficial,” Sacks said, citing cereal fiber as protective against type 2 diabetes and whole grains as protective against cardiovascular death.

“So what that really means is that we need to choose our carbohydrate-based food not necessarily on the glycemic index value, but on the basis of what foods they are — whole grains, fruits, vegetables,” Sacks said. – by Regina Schaffer

Reference:

Sacks FM. The science behind heart healthy nutrition and weight management. Presented at: Cardiometabolic Health Congress; Oct. 21-24; Boston.

Disclosure: Sacks reports no relevant financial disclosures.