Can fiber protect against heart disease?

The only macronutrient that most people in the UK and the US are deficient in is fiber.

With all the high-protein products filling the shelves, this might come as a surprise, but it’s true: More than 90% of us don’t eat enough.

What is fiber?

Fiber is a carbohydrate present in all plants that our bodies can’t digest. Because our digestive enzymes can’t break it down, it travels to the far end of our intestines, where it feeds our gut microbiome.

In return, our grateful microbes produce healthy bioactive compounds as they ferment the fiber.

In this article, we’ll focus specifically on the fascinating links between consuming fiber and heart health. If you’d like more general information on fiber’s health benefits, try this article.

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Fiber and heart health: The evidence

Heart disease has been the number one killer in the UK and the US for more than 100 years. 

Although medication and treatment have advanced, prevention is always better than a cure.

For this reason, scientists have long focused on lifestyle changes that can reduce your risk.

Initial research into diet and heart health focused on fats, particularly high intakes of saturated fats. More recently, the focus has widened to include other macronutrients like fiber. 

The authors of a meta-analysis that re-analyzed data from 22 studies concluded: “Greater dietary fiber intake is associated with a lower risk of both cardiovascular disease and coronary heart disease.”

In a recent article by ZOE, we investigated links between fiber and the risk of developing type 2 diabetes. As with heart health, there’s good evidence that fiber reduces the risk. 

This is important because developing type 2 diabetes is a risk factor for heart disease. So, by reducing diabetes risk, you also reduce your cardiovascular risk.

Other researchers have explored the roles of different types of fiber in heart health risk. Although there is less evidence, it seems that the fiber found in whole grains, bran, and cereal fiber may be particularly protective.

The authors of another review conclude that “dietary fiber [...] may beneficially influence all parameters of body weight management and metabolic disorders related to obesity with consequent advantages on global cardiovascular risk.”

In other words, focusing on increasing fiber intake may reduce your risk of obesity and metabolic conditions, thereby benefiting overall heart health. 

It seems that dietary fiber can support heart health in a number of ways.

What about people who already have heart problems?

As we’ve seen, upping fiber intake can help protect your heart. But can it also support people who already have cardiovascular disease?

This topic has been investigated less. However, there’s good evidence that if someone with cardiovascular disease increases their fiber intake, they will also experience benefits.

The authors of a review explain that, alongside standard medical treatment, increasing fiber intake is likely to reduce the risk of future cardiovascular events, such as heart attack and stroke. 

They also suggest that a higher fiber intake will reduce their risk of premature death from cardiovascular disease.

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What should you do?

Taken together, the evidence shows that if you want to protect your heart, upping your fiber intake is a great start. 

At the same time, if you already have heart disease or risk factors for cardiovascular disease, like type 2 diabetes or obesity, consuming more fiber may help.

We know that some fibers are more easily fermented by certain bacteria, which is why different gut microbes prefer different types of fiber. For this reason, it's best to get your fiber from a variety of whole foods. 

That way, you also get all the other nutritional benefits of plants, such as polyphenols, vitamins, and minerals. Here’s a list of some particularly high-fiber plants to get you started.

As we mentioned, you should aim for at least 30 grams per day. But tracking this precisely can be difficult. 

The app also tells you whether products have any risky additives or processing you should be aware of. Download it here and see if you can hit your 30-gram fiber target today.

It’s also worth mentioning that if you don’t currently eat a lot of fiber, you might experience some bloating initially. So, take it slow, and the symptoms should pass after a few days.