There’s more to heart health than controlling cholesterol and blood pressure. Keeping chronic inflammation in check also plays a big role — another factor where diet can make a difference, a new study has found.
People who ate lots of red meat, processed meat, refined carbohydrates and other foods with higher “inflammatory potential” had a 46% higher risk of heart disease and a 28% higher risk of stroke compared to people who ate an anti-inflammatory diet rich in fruits and vegetables, researchers reported this week in the Journal of the American College of Cardiology.
That may be happening because inflammation drives changes in blood vessels, leading to the development of atherosclerosis — the buildup of fat, cholesterol, calcium and other substances inside the arteries, said Dr. Jun Li, lead author of the study.
“Diet can help,” Li, a research scientist in departments of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health, told TODAY.
A healthy diet “can help us manage chronic low-grade inflammation… and help us maintain a balance inside your body, but a bad diet can increase the basic inflammation level of our body,” she noted.
The results are based on three study cohorts that included more than 166,000 women and almost 44,000 men, with 24 to 30 years of follow-up. The participants regularly filled out questionnaires about their diets, to which Li and her co-authors assigned a score based on that eating pattern’s potential to cause inflammation.
When the researchers analyzed the scores and the participants’ health, they found eating more inflammatory foods was associated with higher levels of pro-inflammatory biomarkers and triglyceride levels in the blood, along with reduced levels of high-density lipoprotein cholesterol — the “good” cholesterol that can lower the risk for heart disease and stroke.
Diets with higher inflammatory potential were “significantly associated” with a higher incidence of heart disease and stroke, even after the results were adjusted for alcohol use, smoking, salt intake and blood pressure.
“We controlled for almost every risk factor, mediator and other confounders we can think of and the association between dietary inflammatory potential and cardiovascular disease risk still remained super robust,” Li said. “This part was surprising to us.”
How to lower chronic inflammation:
The goal is to eat fewer foods with higher pro-inflammatory potential such as:
- Red meat
- Processed meat
- Organ meat
- Refined carbohydrates, such as white flour and white rice
- Sweetened beverages
Instead, eat more foods with higher anti-inflammatory potential, including:
- Green leafy vegetables: kale, spinach, cabbage, watercress, romaine lettuce, Swiss chard, arugula and endive
- Dark yellow vegetables: pumpkin, yellow peppers, beans and carrots
- Whole grains: wheat, oat, rye, buck wheat and millet
- Fruits: especially blueberries, pomegranate, orange, cherries, strawberry, apples and pears
- Tea, coffee and red wine
- Extra virgin olive oil
- Fatty fish
These foods contain anti-inflammatory compounds such as vitamins, carotenoids, polyphenols, fiber and long-chain omega-3 fatty acids.
A separate study in the same issue of the Journal of the American College of Cardiology found incorporating a daily 1-2 ounce dose of walnuts into the diets of older people “significantly reduced” several inflammatory biomarkers after two years. The study was supported by a grant from the California Walnut Commission.
It was the largest and longest nut trial to date, and shows why the anti-inflammatory effects of walnuts can reduce the risk of heart disease beyond lowering cholesterol, wrote Dr. Ramon Estruch, a physician at the Hospital Clinic in Barcelona, Spain, in an accompanying editorial.
“When choosing the foods in our diet, we should beware of their pro- and anti-inflammatory potential,” he advised.
The best way to do that may be to follow the Mediterranean diet, Li said. It naturally includes lots of fruits, vegetables and whole grains while minimizing red meat. Since it’s not possible to eliminate all inflammatory foods for most people, she suggested taking small steps towards eating fewer of them. Replace refined grains with whole grains, for example.
The current study doesn’t address whether a person who has been eating lots of pro-inflammatory foods for years can still reduce their heart disease risk by switching to an anti-inflammatory diet, but Li said other research offers hope that would happen.
Making such a switch can lead to weight loss, previous studies have shown.
“From this perspective, it is highly possible that changes in dietary inflammatory potential will also have a long-term effect of cardiometabolic disease risk,” Li said.