It has become increasingly clear that a diet rich in prebiotic fiber foods can reduce risks for heart disease by improving blood lipid levels. Furthermore, the ability of prebiotics to help restore gut balance and reduce systemic, chronic inflammation pays downstream dividends that also support heart health. In this article, we'll explore the connection between prebiotics and heart health and discuss the supporting research and science behind it.
Why are prebiotics healthy?
The prebiotic concept is an evolving one. Since the first sweeping definition, introduced by Glenn Gibson and Marcel Roberfroid in 1995, new guidelines have been established to more accurately identify effective prebiotics. The initial definition described a prebiotic as “a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health.” This pioneering definition outlines several key criteria for a prebiotic:
Improves host health: A prebiotic is a substance or a food compound that is consumed for the purpose of improving one’s health, through improving the gut microbiome.
Nondigestible: A prebiotic must move through the upper-digestive tract and reach the colon (large intestine) intact. This is why many prebiotics tend to come from high-fiber foods, as fiber is hard for the body to digest and remains intact all the way through to the colon.
- Stimulates the growth… of bacteria in the colon: One of the key functions of a prebiotic is to feed the beneficial bacteria or microorganisms in the gut, restoring gut balance and gut health.
Since this above definition was created, scientists have also determined that one of the most important end products of prebiotics, which results from feeding the beneficial bacteria in your gut, are short-chain fatty acids (SCFAs) — including lactic acid, butyric acid, and propionic acid. SCFAs have wide-ranging beneficial impacts on host physiology, from helping to maintain gut and immune health to aiding in preventing certain diseases.
Summing up major health benefits of prebiotics, they:
- Support gastrointestinal (GI) health by protecting the lining of intestinal walls and preventing chronic inflammation caused by the contamination of particles across gut walls or lining
- Improve digestive health and certain gut conditions by promoting regularity while improving the quality of stool and reducing the body’s digestive transit time
- Improve blood glucose control and encourage better insulin response
- Support brain health through an upregulating effect on general cognition, learning, and mood
- Modulate energy metabolism and satiety
- Strengthen bone health and density by improving mineral absorption including calcium
- Support heart health by defending gut health and downregulating cholesterol and triglyceride levels, the special focus of the remainder of this report
Learn more about these and more health benefits of prebiotics in: Prebiotic 101.
Prebiotics and heart health
Prebiotics improve blood lipids
Blood lipid profiles are a strong indicator of heart health. Cholesterol levels that are too high raise one's risk of heart disease and cardiovascular events, including heart attack and stroke. Fortunately, daily consumption of fiber — and particularly soluble fiber — can reduce “the bad cholesterol” (low-density lipoprotein cholesterol, LDL-C) levels by at least 5-10%.
Many prebiotics are sourced from high-fiber foods and tend to be soluble fibers themselves, which might explain why prebiotics, such as locust bean gum, beta glucan (oat/barley), and inulin, can positively impact overall blood lipid profiles (reduced total cholesterol, LDL-C, and triglycerides; and improved HDL-C).
- In a study exploring the effects of oat beta glucan on lipid profiles in 75 hypercholesterolemic adults, six grams of oat beta glucan, consumed daily over the course of six weeks, effectively reduced total cholesterol and LDL-C by -0.3 mmol/L, respectively.
- A recent study observing the effects of inulin on cardiovascular markers (including cholesterol and triglycerides) in patients with chronic kidney disease showed that prebiotic intervention, via oral supplementation of inulin at 19g/day for six months, reduced average total cholesterol levels from 201.16 mg/dL to 166.22 mg/dL, reduced triglyceride levels from 130.11 mg/dL to 97.41 mg/dL, and raised “good cholesterol” (HDL-C) from 43.86 mg/dL to 53.00 mg/dL.
- Locust bean gum was shown to effectively reduce total cholesterol levels and LDL-C levels in both hypercholesterolemic patients and patients with normal cholesterol levels. This study also revealed a beneficial impact of locust bean gum consumption on HDL-C levels.
Prebiotics improve the balance of bacteria in your gut
Prebiotics play an important role in gut health, which is ultimately connected to heart health. Gut health is thrown out of whack when the ratio of beneficial bacteria to potential harmful microbes in the gut is out of balance (also known as “dysbiosis”). Dysbiosis may occur as the result of a few different scenarios:
- Alcohol abuse
- Antibiotic use
- High levels of stress
- An unhealthy diet
All prebiotics increase the count of beneficial gut bacteria, particularly of the Bifidobacterium species, and restore a healthier balance within the gut microbiome. (Skip to the section titled “Natural prebiotic foods” to learn which of the many prebiotic fruits, vegetables, grains, nuts, and seeds are most effective at gut rebiosis.)
Some prebiotics, such as resistant potato starch (RPS), simultaneously reduce the growth of harmful bacteria strains (Clostridium, Escherichia coli, Enterococcus, and Bacteroides) while also promoting the growth of beneficial bacteria.
Prebiotics reduce and prevent inflammation
Chronic inflammation stresses the immune system and is associated with increased risk of heart disease, as well as other chronic diseases (including diabetes, cancer, and Crohn's disease).
Physical symptoms of inflammation might manifest as pain, redness, swelling, or heat. However, you can also measure inflammation by use of a CRP blood test, specifically looking for the presence of C-reactive protein (CRP), a protein that your liver makes and releases into the bloodstream in response to inflammation in the body. High levels of CRP indicate that your body is experiencing considerable inflammation, which could be the result of a temporary condition (infection) or a persisting condition (autoimmune disease, lung disease, bowel disease).
Inulin, a prebiotic, has been found to help improve inflammation markers. In a randomized controlled trial (RCT) comparing the effects of 10 grams of inulin against maltodextrin (a white powder derived from corn, potato, rice, or wheat) for eight weeks in women with type 2 diabetes, the inulin group experienced a more dramatic decrease (-35.6%) in a marker of inflammation (high-sensitive C-reactive protein, or hs-CRP); and a simultaneous improvement in blood sugar markers (fasting blood sugar, fasting insulin, and insulin resistance). Another study observed that the supplementation of inulin with a probiotic strain, Lactobacillus Rhamnosus G (LGG), significantly improved inflammation markers more than did either supplement on its own.
Whether resistant starch has a similar impact upon inflammation markers remains an evolving area of research. A 2020 meta-analysis observed a strong association between the amount of resistant starch consumed and the degree of reduction in interleukin 6 (an interleukin involved in the inflammatory process). However, findings from other studies, such as this study, do not point to a significant relationship between this prebiotic and bio-inflammatory markers.
Natural prebiotic foods
Natural foods that fall under the prebiotic group tend to contain lots of fiber. The following foods, which are but a small sampling of the hundreds of great prebiotic sources readily available in plant-based whole foods, help balance the gut microbiome and contribute to greater heart health.
- Grains: barley, oats, wheat bran
- Roots: burdock, jicama, yacon, konjac, and chicory
- Vegetables: garlic, leek, Jerusalem artichokes, asparagus, onions, mushrooms, seaweed, beets, broccoli, Brussels sprouts, fennel, kale, and dandelion greens
- Fruits: bananas, apples, blueberries, citrus, pears, nectarines, watermelon, cherries, grapes, raspberries, avocados, kiwi
- Legumes/nuts/seeds: soybeans, chickpeas, lentils, flaxseeds, kidney beans, almonds, pistachios
Specific to heart health, there are many prebiotic fibers in the above foods that exert notable impacts, but three in particular are interesting to highlight.
- The extensively-researched prebiotic, inulin, is commonly found in such natural food sources as chicory root, Jerusalem artichokes, asparagus, dandelion greens, garlic, leeks, soybeans, oats, and wheat. Inulin is associated with beneficial effects on blood lipids and inflammation.
- Beta glucan, another prebiotic with beneficial effects on blood lipids, is abundant in whole grains including oats, barley, wheat, and rye, as well as certain mushrooms and seaweed.
- Resistant starch, a prebiotic that has demonstrated an association with improved inflammation in some (but not all) clinical studies, can be found in grains, seeds, legumes, potatoes, green bananas, and rice.
Although the above prebiotic fibers may seem to have a more direct impact on heart health, in reality all prebiotics support heart health by restoring gut health and improving blood lipids.
A prebiotic superblend: Eden’s 3-in-1
The gut microbiome hosts a wide range of gut bacteria and microorganisms. Different prebiotics feed and benefit different microorganisms. Therefore, daily consumption of a wide variety of prebiotics, preferably sourced from whole foods, is likely the most beneficial way to restore balance in the gut microbiome. While a comprehensive and consistently rich diet of plant-based foods will typically ensure that you benefit from enough high-fiber prebiotic foods, it is not always convenient or accessible to obtain and consume them — which contributes to the sad fact that most Americans eat less than half the daily recommended amount of dietary fiber per day.
Fortunately, prebiotic supplements are available to help close the daily fiber intake gap.
3-in-1 Synbiotic Superblend
Eden’s 3-in-1 Synbiotic Supplement contains a superblend of five prebiotics that each tackle a different aspect of digestive, gut, heart, and immune health.
Resistant potato starch (RPS) is a soluble fiber that increases production of beneficial gut bacteria and short-chain fatty acids (SCFAs). While the particular Eden’s formulation of RPS, called Solnul™, increased the production of an important anti-inflammatory molecule, called IL-10, by 3.5-fold, the debate remains whether RPS actually prevents gut and systemic inflammation. However, research has concretely shown a positive impact of RPS on cholesterol levels. Furthermore, resistant starch may also aid in weight management — a key element of cardiovascular health — by improving satiety, which keeps you full for longer, and reducing the amount of stored fat in the body.
In addition to these five prebiotics, Eden's 3-in-1 also contains powerful probiotics — which is why this supplement is considered a synbiotic; as well as a group of polyphenols that further support gut health and heart health. To learn more about how all three of these nutrient groups interact to beneficially impact gut health and heart health combined, see How does the gut affect heart health?
Heart health in perspective: Prebiotics, lifestyle changes, and other dietary strategies
Of course, heart health is impacted by more than your prebiotic fiber intake, although this one factor is indeed a major one. Other dietary strategies to improve heart health include:
Avoiding saturated fats and trans fats, which raise levels of low-density lipoprotein (LDL, also known as “bad” cholesterol), while upping your consumption of healthy fats such as monounsaturated fats (found in avocados and some nuts and seeds) and omega-3s (found in fatty fish and vegetable oils) that increase levels of high-density lipoprotein, or HDL (the “good” cholesterol).
Limiting your consumption of red meat, which promotes the production of trimethylamine N-oxide (TMAO), a byproduct of gut bacteria digestion of nutrients found in animal products, including red meat. TMAO is highly associated with atherosclerotic plaques and elevated risk for cardiovascular disease.
Adding into your diet some healthy probiotic (fermented) foods, like yogurt or kefir, known for their digestive benefits, but increasingly being researched for possible benefits to the heart, including reduced blood pressure, general stimulation of the immune system, and reduced visceral fat; and polyphenol-rich foods, like kiwifruit and green tea, which have antioxidants that reduce cellular stress and so may confer certain protections against cardiovascular diseases. Learn more in Do probiotics lower cholesterol? and What are the heart health benefits of polyphenols?
- Limiting your sodium intake: While this dietary factor may not affect gut health per se, it is of vital importance for cardiometabolic health. A 2018 review confirmed numerous previous studies concluding that excessive sodium intake is associated with several adverse effects on health outcomes, most notably elevated blood pressure, putting you at higher risk for CVD as well as cerebrovascular diseases (e.g., stroke), kidney diseases and type 2 diabetes.
Add to the above dietary recommendations these important lifestyle strategies:
Regular exercise: Even moderate levels of aerobic exercise, or cardio, can improve your lipid profile and decrease your risk for CVD by raising HDL-C levels while lowering triglyceride levels. (The evidence regarding the effects of exercise on LDL levels is mixed.)
- Better sleep habits: When your body doesn’t get enough quality sleep, it can negatively affect your gut and cardiometabolic health, as well as your mood and brain function.
- Limited alcohol consumption: Alcohol, including red wine (which was at one point touted for its potential health benefits), has a negative impact on brain and heart health. Long term and excessive consumption of alcohol increases the risk of heart conditions including high blood pressure, heart disease, and stroke.
More and more, we learn how indispensable a healthy gut is to heart health as well as overall health. Prebiotics support gut and heart health by balancing the gut microbiome, feeding beneficial gut bacteria, improving blood lipids, and reducing gut inflammation. Prebiotics are abundant in fruits, vegetables, legumes, nuts and seeds. And prebiotics are even more effective when they work in tandem with probiotics, which you can obtain by taking a synbiotic supplement. Eden's 3-in-1 Synbiotic contains a carefully selected menu of prebiotics and probiotics, and also includes beneficial polyphenols that provide gut-improving and heart-health benefits to help you feel better from the inside-out.