Can cocoa consumption help reduce risks?

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Scientists have observed positive effects of cocoa consumption on health, particularly on heart health. Emilija Manevska/Getty Images
  • Consuming cocoa extract or very dark chocolate has been shown to reduce several cardiovascular risk factors in a new meta-study, a review of other studies.
  • Cocoa consumption appears to reduce overall blood pressure, as well as bad cholesterol and blood sugar.
  • However, it does not appear to have any effect on body weight or a primary biomarker of diabetes.
  • Different foods, such as cocoa, may promote heart health, although experts say an overall healthy diet is more effective at reducing cardiovascular disease.

A new meta-study of randomized controlled trials examines the effect of cocoa consumption on cardiovascular disease risk factors.

Cocoa consumption has been associated with varying degrees of improvement in total and LDL (“bad”) cholesterol, systolic and diastolic blood pressure, and fasting blood glucose.

All of these are risk factors for heart or cardiovascular disease.

The researchers also found that cocoa consumption had no effect on body weight, body mass index (BMI), waist circumference, triglycerides, “good” HDL cholesterol and HbA1c, an important biomarker of diabetes.

The meta-study analyzed 31 randomized controlled trials that monitored the above risk factors. Trials eligible for analysis involved a total of 1,986 participants. In total, the intervention group included 1,110 participants who consumed either cocoa extract or dark chocolate containing 70% or more cocoa for at least four weeks. The control group included 876 participants who consumed placebo or white or milk chocolate containing less than 70% cocoa.

People eligible for the trials were all aged 18 years or older. Of the 31 studies analysed, four included only older adults and five only younger adults.

The majority of studies included participants with one or more health conditions, including metabolic syndrome (3), dyslipidemia (4), prehypertension or hypertension (2), excess weight (4), type 2 diabetes (7), and insulin resistance (1). The remaining 13 studies included only healthy participants without known cardiovascular risk factors.

The analysis revealed, on average:

  • an 8.35 mg/dL reduction in overall cholesterol
  • a 9.47 mg/dL reduction in LDL cholesterol
  • a 4.91 mg/dL decrease in fasting blood glucose
  • a 2.52 mmHg reduction in systolic blood pressure
  • a 1.58 mmHg decrease in diastolic blood pressure.

The study is published in MDPI.

In the United States, heart disease is the leading cause of death across all population groups, accounting for one in five deaths in 2021, according to the U.S. Centers for Disease Control and PreventionIt affects women, men and all ethnic and racial groups.

Every 33 seconds, someone in the United States dies from cardiovascular disease.

Diet is strongly implicated in cardiovascular diseases. American Heart Association emphasizes the importance of good nutrition throughout life as a strong defense against heart problems.

There is growing interest in identifying foods that are particularly good for the heart. One of these is cocoa because of the beneficial compounds it contains.

“Cocoa is a good source of catechins and other polyphenolic compounds like flavanols known for their antioxidant and anti-inflammatory properties, which may support cardiovascular health,” said Michelle Routhenstein, MS, RD, CDCES, a preventive cardiology dietitian at EntirelyNourished.com, who was not involved in the new study.

“Cocoa is rich in flavonoids,” Routhenstein says, “including epicatechin, a compound that helps support rich stores of nitric oxide in the body, which helps support heart and blood vessel health.”

Jayne Morgan, MD, cardiologist and executive director of community health and education at Piedmont Healthcare Corporation in Atlanta, Georgia, listed other heart-healthy foods: “Fatty fish, olive oil, nuts, berries, walnuts, beans, green leafy vegetables, whole grains.”

Nevertheless, Routhenstein described the strongest prescription for heart health:

“A nutrient-dense and diverse diet, including fruits, vegetables, oily fish, nuts, lean proteins and whole grains, provides a broader range of nutrients and compounds protective against cardiovascular disease.”

So it’s important to view cocoa “as part of a broader, heart-healthy diet rather than as a stand-alone protective measure against cardiovascular disease,” Routhenstein said.

She suggested that for those with a sweet tooth, “enjoying a square of (at least) 70% dark chocolate with berries, or adding cocoa powder to a hot drink can be a satisfying and healthy evening treat.”

Routhenstein cautions, however, that excessive consumption of chocolate in any form, including dark chocolate, “can lead to high sugar and saturated fat intake, which can negatively impact heart health. So quantity matters.”

“You also need to be cautious during pregnancy,” Morgan said of overindulging in chocolate. While some research suggests potential benefits in moderation, pregnant women should be especially mindful of chocolate’s added sugar and caffeine content.

Morgan said: “Even a reduction of 2.52 mmHg in systolic blood pressure and 1.58 mmHg in diastolic blood pressure is positive.”

At the same time, she expressed concern about the varying amounts of cocoa consumed and the uncertainty about the origin of that cocoa.

She pointed out that the amounts of cocoa ingested by participants varied considerably: from 1.4 g per day to 50 g per day.

“Additionally,” Morgan said, “the multiple sources of cocoa, from beverages to bars to candy and more — with varying amounts of other ingredients such as milk and sugar — create a great deal of heterogeneity within the population.”

This also raises the question of inconsistencies in the cocoa manufacturing processes considered in the studies.

Routhenstein noted: “It is important to note that the availability of epicatechin in cocoa products may be affected by processing and storage conditions, as it is heat sensitive and can degrade if not handled carefully during manufacturing.”

The meta-study found no effect of cocoa on a diabetes marker, HbA1c, although it appeared to cause a beneficial lowering of blood sugar.

Morgan described the improvement in blood sugar as “a reflection of the level of control of diabetes and blood sugar in the body. Persistently high levels of glucose in the blood can damage blood vessels in the heart as well as other parts of the body, leading to peripheral vascular disease.”

As for HbA1c, Morgan said, longer studies are needed to draw conclusions about cocoa and diabetes.

“Diabetes is a risk factor for cardiovascular disease because it increases the risk of developing atherosclerosis, which increases the risk of heart attack,” Morgan said. “In addition, diabetes is associated with chronic inflammation, a cardiac risk factor, as well as obesity.”

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