My Molecular Health
The Why Behind 'Eat Fruit & Vegetables
What Are Flavanol-3s? The Tea On The New Dietary Recommendation For This Important Nutrient, According To A Food Scientist
The smell of freshly baked apple cinnamon raisin bagels (whole grain, of course) and a cup of hot tea or cocoa in the morning takes me back to my grandmother’s kitchen. But would it surprise you that there was some truth to my grandma’s favorite mantra,“an apple a day keeps the doctor away?”
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My grandmother lived to be 95 years old and oversaw a 75-plus-acre farm until right before she passed in 2013. I don’t remember a single visit where there weren’t fresh fruits and vegetables from her garden stacked on the counter, and apples from my family’s orchard. She also always had a pitcher of freshly brewed iced tea (remember that as you read this article). She drank five cups of unsweetened iced tea every day for as long as I can remember.
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As it turns out, my grandmother was on the right track for long-term health and vitality. She had low blood pressure, normal cholesterol levels and no issues with her blood sugar levels. So, it wasn’t surprising to me that after over a year of reviewing hundreds of millions of dollars and decades of research, our group of internationally-recognized scientists within the Academy of Nutrition and Dietetics published the first intake recommendation around a non-essential set of nutrients called flavan-3-ols.
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The intake recommendation—published in Advances in Nutrition—recommends that 400 to 600 milligrams daily of flavan-3-ols may reduce risk associated with cardiovascular disease and diabetes.
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So, what exactly does that mean? Below, I explain what flavan-3-ols are—and why this new recommendation is noteworthy.
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What Are Dietary Bioactive Compounds?
Food scientists and researchers (like me) are learning more and more about the benefits of specific plant compounds called bioactives. The National Institutes of Health (NIH) defines bioactives as “constituents in foods or dietary supplements other than those needed to meet basic human nutritional needs, which are responsible for changes in health status.” While vitamins and minerals like iron, calcium and vitamin D are essential for the functioning—and even survival—of humans, bioactive compounds (most derived from plants) are not necessarily required to survive, but may have significant health benefits. Examples of bioactive compounds include carotenoids (beta-carotene, lycopene, lutein), flavonoids (flavan-3-ols, anthocyanins, isoflavones), cannabinoids (CBD), phytosterols, glucosinolates and thousands more.
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For example, we know that higher intakes of certain foods that contain bioactive compounds can help prevent the onset of most chronic diseases such as heart disease, cancer, type 2 diabetes, Alzheimer’s, dementia and others. After decades of debate, the scientific community has finally decided that the evidence is sufficient to move forward with an official intake recommendation for what is arguably the most studied group of dietary bioactive compounds: The flavan-3-ols.
Are You Getting Enough Flavan-3-ols?
Intake guidelines published in Advances in Nutrition “may help improve blood pressure, cholesterol levels, and blood sugar.”
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Cardiometabolic disease, a group of disorders including hypertension, dyslipidemia, insulin resistance and abdominal adiposity, underlies and increases the risk of cardiovascular disease as well as type 2 diabetes. According to the World Health Organization (WHO), “cardiovascular diseases are the leading cause of death globally.” An estimated 17.9 million people died from cardiovascular disease in 2019, representing 32% of all global deaths. In addition, WHO notes that “the number of people with diabetes rose from 108 million in 1980 to 422 million in 2014,” with the prevalence rising more rapidly in low- and middle-income countries.
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Research has shown the benefits of adhering to a healthy diet to lower the risk of cardiometabolic disease. Moreover, there is a growing body of research that suggests that certain bioactives—specific food components beyond those needed to maintain basic human nutrition—may also play an important role in lowering the risk of cardiometabolic disease.
Among these health-promoting bioactives are flavan-3-ols, the most highly consumed subclass of flavonoids. Flavan-3-ols are commonly found in tea, apples, pears, berries, chocolate, and cocoa products.
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In recognition of flavan-3-ols’ potential to lower the risk of cardiometabolic disease, the Academy of Nutrition and Dietetics assembled an Expert Panel to develop an intake recommendation for flavan-3-ols that optimizes cardiometabolic outcomes. The Panel consisted of six members. Each candidate was evaluated based on a set of standard criteria, including experience in the subject matter and conflicts of interests. Candidates with the highest scores were selected for the Expert Panel, with the highest scoring candidate selected as the Chair. The Panel’s intake recommendations, Flavan-3-ols and Cardiometabolic Health: First-Ever Dietary Bioactive Guideline, were published in Advances in Nutrition, the international review journal of the American Society for Nutrition.
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In order to make their recommendations, the Panel analyzed the results from 157 randomized controlled trials and 15 cohort studies published between 1946 and March 2019. All the studies used subjects 18 years and older. Moreover, all the studies the Panel analyzed had been previously reviewed in a recently published systematic review and meta-analysis.
Among the general adult population, the Panel recommended “increasing consumption of nutrient-dense foods rich in flavan-3-ols and low (or absent) in added sugars, including but not limited to tea, apples, berries, and cocoa.” Specifically, the Panel found that “moderate evidence supporting cardiometabolic protection resulting from flavan-3-ol intake in the range of 400-600 mg/day was supported by the literature.” Overall, they believe that “consumption of dietary flavan-3-ols may help improve blood pressure, cholesterol levels, and blood sugar.” The Panel stressed that “the beneficial effects were observed across a range of disease biomarkers and endpoints.”
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The Panel did caution that “this is a food-based guideline and not a recommendation for flavan-3-ol supplements,” which may cause gastrointestinal irritation or liver injury, particularly when taken in excess or on an empty stomach.”
Overall, the Panel pointed to a growing body of research that demonstrates higher consumption of flavan-3-ols may reduce the risk of certain cardiometabolic diseases and related mortality. The Panel did note that their guideline was developed from research on the general adult population: “additional research evaluating flavan-3-ol intake earlier in the lifespan is warranted as dietary habits adopted earlier in life may contribute to the magnitude of effect of flavan-3-ols on cardiometabolic health.”