Soluble fiber is gaining popularity in the recent years, and is becoming renowned as a food that has a number of protective effects on our health and heart.
Broadly classified, fibers that are present in our foods are either insoluble or soluble. In simple terms, insoluble fiber does not dissolve in water, while soluble fiber can mix and form a thick gel with it.
Another way of classifying dietary fiber is as a dietary source (fruits, vegetables, cereals, legumes etc) or as a supplement.
In 1972, a paper published in the American Journal of Clinical Nutrition by Trowell and group discovered a link between dietary fiber and heart disease. Since then, a fair bit of research has been conducted and there is now enough scientific evidence that soluble fiber can protect our heart.
Here I will review some of the ways that it does so.
Soluble Fiber Aids Weight Loss
Remember the ‘gel’ is mentioned above that soluble fiber becomes when it comes into contact with water?
Well, this gel that has a property of slowing down stomach emptying. This in turn keeps your stomach fuller for longer.
Why is this good?
By having your stomach fuller for a longer period of time, you are unlikely to snack on junk food, which we all know is unhealthy for us.
But that’s not all.
Dietary fiber is also believed to stimulate the release of certain compounds in the gut. These compounds can stimulate the ‘satiety center’ in the brain, thus leaving you with a feeling that you have eaten enough food.
So, lower your food intake, and you can lower your weight.
Soluble Fiber Reduces Cholesterol Levels
If you read our article on cholesterol, you would know that there is a good cholesterol (HDL) and a bad cholesterol (LDL). If you want to keep your heart in good shape, you must reduce your bad cholesterol levels.
Clinical trials have shown that consuming modest amount of soluble fiber on a regular basis can result in your LDL cholesterol i.e. bad cholesterol level dropping.
A reduction of LDL levels by 10% can reduce the risk of developing heart disease by 10%.
It appears that this effect is also present if you are medication to reduce your cholesterol. Moreyra et al conducted a clinical study comparing simvastatin (a cholesterol lowering agent) and simvastatin combined with a 15 gm/day high fiber diet was conducted to assess this effect.
The group that had the medication and soluble fiber together had a 36% reduction in their bad LDL cholesterol.
But how does soluble fiber affect cholesterol levels?
Well, the mechanisms are quite complex. It can modify the enzymes that are responsible for maintaining cholesterol levels. It can increase the number of proteins that bind to LDL, resulting in a greater degree of removal of LDL from the blood.
Soluble fiber does not have a significant effect on triglyceride levels and HDL levels.
Soluble Fiber Reduces Blood Pressure
There are a number of clinical studies that have shown that consuming good quality dietary fiber on a regular basis may reduce blood pressure. High blood pressure is a recognised risk factor in the development of heart disease.
In one clinical trial conducted by Ascherio and group, it was found that greater the fiber intake (derived from fruits), the lower was the blood pressure. Studies looking at blood pressure control over a period of 24 hours found that fibers derived from oats and psyllium reduced systolic blood pressure by 5 to 6 mmHg.
It may not seem like much, but a reduction of just 5 mmHg of systolic blood pressure can reduce your risk of fatal heart disease by 9%. That’s significant.
In another study that looked at people with high blood pressure, it was found that those who consumed oats on a regular basis reduced their requirement for blood pressure medicines by 73%.
In fact, the role of fiber in blood pressure management has now become so important, that expert bodies are recommending that our diet should have at least 24 grams of fiber out of each 1600 kcal consumed in a day.
Soluble Fiber Controls Blood Sugars
It is well known that diabetes increases your risk of heart disease.
Studies looking at regular consumption of barley with added soluble fiber have found a reduction in blood sugar spikes after a meal by 20 – 30%. In other words, the post prandial sugar levels remarkably decrease.
Other clinical studies have shown a beneficial effect of fiber consumption on fasting blood sugar and HbA1c levels.
One reason why people in India develop diabetes is the presence of ‘insulin resistance’. This means our body is resistant to the hormone insulin that is produced by our pancreas.
Insulin is required to keep blood glucose levels under check. If we are insulin resistant, the blood glucose levels can rise and lead to pre-diabetes and diabetes.
Soluble fiber appears to enhance insulin sensitivity. This property is not seen with insoluble fiber, though some scientists debate this.
What Are The Best Sources of Soluble Fiber
I thought I would include a table that I saw in an article published in the Journal of Family Practice by Tatyana Shamliyan et al, which beautifully summarises the total soluble fiber content in commonly consumed foods.
As you can see in the table above, the highest sources of soluble fiber are lima beans, pearl barley and northern beans along with carrots and brussel sprouts. While these are widely available in western countries, they are not so easily available in India. Psyllium seeds are available if you hunt around for them.
Some studies have suggested that fiber derived from cereals are the best kind of fiber.
There are plenty of supplements that are currently available that provide some form of soluble fiber. These are often used to help treat constipation rather than to help your heart.
Newer supplements are now available that are research based and proven to reduce cholesterol, blood sugar and overall heart disease.
Soluble fiber consumption is a great way to naturally reduce your risk of heart disease and diabetes. Make sure you get enough of it in your daily diet. If you can’t, try a high quality supplement.