Most people with high triglycerides are told to cut down on certain types of foods, like trans fats and added sugars. Rarely, however, do health care providers offer advice about which specific foods patients should enjoy more often. A new study might just change that.

A high triglycerides diet that contains foods that are naturally rich in polyphenols lowers triglycerides and reduces oxidative stress, according to results of a randomized controlled trial recently published in The American Journal of Clinical Nutrition.[1]

What are polyphenols?

Polyphenols are naturally occurring compounds that exist in plants and plant products, including fruits, vegetables, nuts, herbs, cocoa, and tea. While polyphenols are not essential nutrients, research in the last decade has revealed their dramatic role in improving health. For example, consuming plenty of foods high in polyphenols is associated with a lower risk of cardiovascular disease.[4]

Thousands of different polyphenols exist and are classified based on their chemical structure. Four classes of polyphenols are found in foods: flavonoids, lignans, phenolic acids, and stilbenes. Research on the impact of polyphenols on cardiovascular disease has primarily focused on the flavonoid class, which is divided into the following primary six sub-classes:

1. Flavanols, such as quercetin, are ubiquitous in plant foods and most concentrated in spices, berries, and cocoa.
2. Flavanones, such as naringenin and hesperetin, are found in citrus fruits.
3. Flavan-3-ols, such as epicatechin and gallocatechin, are found in black and green tea.
4. Flavones, such as luteolin, are found in certain green vegetables and herbs such as green peppers, parsley, thyme, and celery.
5. Anthocyanins, such as proanthocyanidins, are prominent in foods that are red/purple in color, such as berries, apples, plums, and red wine.
6. Isoflavones resemble estrogen in structure and, therefore, are classified as phytoestrogens. They are found in soy products such as tofu, roasted soy nuts, and miso.

Critical to their beneficial impact on cardiovascular disease is polyphenols’ (especially the flavonoids’) role in countering inflammation and oxidative stress, both of which are now known to be key underlying causes of cardiovascular disease.[3]In addition, some polyphenols, such as proanthocyanidins, also directly reduce triglycerides. While researchers are still trying to figure out the exact mechanisms by which they lower triglyceride levels, it appears that proanthocyanidins regulate the expression of certain genes that control how fats are metabolized by the liver.[5]

Foods high in polyphenols create the perfect high triglycerides diet

In the recent study, one of the first controlled studies of its kind, researchers at Federico II University in Naples, Italy, evaluated the effects of diets naturally rich in polyphenols and/or omega-3 fatty acids from fish on triglycerides and oxidative stress. The study involved 86 overweight or obese subjects with a large waist circumference (men >40.2 inches, women >34.6 inches) plus one or more of the following components of the metabolic syndrome: triglycerides≥150 mg/dl, HDL cholesterol <40 mg/dl (men) and <50 mg/dl (women), or fasting blood sugar (glucose) 100 to 125 mg/dl.

Each subject was randomly assigned to one of four diets, all containing the same number of calories.

• Diet 1 (the control diet) was low in polyphenols and omega-3s. It was designed to be low in fish, nuts, legumes, and oils rich in monounsaturated fatty acids (olive oil). It contained only vegetables and fruits that were low in polyphenols.
• Diet 2 was high in omega-3 fatty acids. It included fish at least three times per week and large, leafy vegetables.
• Diet 3 was high in polyphenols. It contained extra virgin olive oil, green tea, berries, fruits rich in polyphenols (such as red grapes, apples, and citrus fruits), dark chocolate, and decaffeinated coffee.
• Diet 4 was rich in both omega-3s and polyphenols.

Results of eating ample polyphenols

After eight weeks on the various diets, only the groups eating the high polyphenol diets experienced significantly reduced triglyceride concentrations. Both fasting triglycerides and triglycerides after eating were significantly reduced.

The concentration of large very-low-density lipoproteins (VLDLs) was also significantly reduced in the groups eating the polyphenol-rich diets. VLDLs are a type of protein made by the liver to transport triglycerides. They contain both triglycerides and cholesterol and are converted in the bloodstream to LDL cholesterol.

The high-polyphenol diets also led to significant reductions in oxidative stress, whereas the diet high in omega-3 fats did not. The reductions in oxidative stress correlated directly to the changes in triglycerides and VLDLs.

While high doses of omega-3 fatty acids from fish have been shown in numerous studies to lower triglycerides, the subjects on the highomega-3 diet didn’t seem to be consuming enough omega-3 fatty acids from diet alone to make a significant difference in their triglycerides. Nor did the omega-3s result in significantly lower amounts of oxidative stress. However, the polyphenols from the high-polyphenol diet alone were enough to significantly lower triglyceride levels and reduce oxidative stress. The researchers concluded: “Diets naturally rich in polyphenols positively influence fasting and postprandial triglycerides and reduce oxidative stress.”

How to lower your triglycerides using a polyphenol-rich diet

To follow a high triglycerides diet and lower your risk of heart disease and type 2 diabetes, eat plenty of darkly pigmented fruits and vegetables, aiming for a vibrant, rainbow-like spectrum of these foods:

• extra virgin olive oil
• green tea
• berries, especially blueberries
• fruits  such as citrus fruits, plums, apples, and grapes
• dark chocolate
• decaffeinated coffee
• vegetables such as lettuce, spinach, and other leafy greens, peppers, and celery
• Fresh herbs such as parsley and thyme
• Spices such as cinnamon and turmeric
• red wine
• soy products such as tofu, roasted soy nuts, and miso

Also include fish (and/or a fish oil supplement) and large green leafy vegetables for extra cardiovascular risk reduction. Your body will thank you for years to come, especially if you take care of your cholesterol and heart health using additional natural therapies.

Have you tried eating more polyphenols to lower your triglycerides? If so, how did it work? Do you have a favorite polyphenol-rich recipe? Please share your experience in the comments section below.

[1] Am J Clin Nutr. 2014 Mar;99(3):463-71.

[2] Clin Chim Acta. 2014 Apr 20;431C:131-142.

[3] J Clin Endocrinol Metab. 2012 Sep;97(9):2969-89.

[4] Curr Atheroscler Rep. 2013 May;15(5):324.

[5] J Nutr Biochem. 2014 Feb;25(2):151-6.

This post originally appeared in 2014 and has been updated.