What Do Plant Sterols, Fiber, and Insulin Mean for Heart Health?

Plus, how to get the most out of a triglycerides test

By Roberta H. Anding, MS, Baylor College of Medicine and Texas Children’s Hospital
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily

Did you know that a plant compound found in margarine and orange juice can lead to a healthier heart? And why exactly is insulin resistance linked to heart disease? Professor Anding reveals the details.

Woman juicing oranges for juice
Manufacturers have introduced orange juice products that are fortified with stanol esters from plants to help fight against developing heart disease. Photo By Milan Ilic Photographer / Shutterstock

Sterols and Heart Health

When it comes to preventing heart disease, research is emerging about compounds called sterols. Plants and animals contain sterols and remember that cholesterol is a sterol.

However, some plants have sterols that can act as cholesterol imitators, blocking the absorption of cholesterol from the gut. Food manufacturers are adding these to products like margarines.

The label will list them as “plant sterols” or “plant stanols.” A whole line of orange juices on the market, such as Minute Maid® HeartwiseTM, include stanol esters. Often the sterols in this case are soybean derivatives. Additionally, they’re found in breakfast bars or supplements. 

Research has found that sterols are slightly more effective in liquid form or semi-liquid form. Thus, orange juice might be a better idea than a breakfast bar.The science suggests that two grams of plant sterols per day can lower your cholesterol by up to 10%.

Although estimates vary on the cholesterol-lowering effect of the sterols and stanols in Pistachios, some studies suggest around an 8% cholesterol-lowering effect. Thus, part of the reason that nutritionists and other experts claim that nuts are heart-healthy is due to the stanol and sterol esters.

Dietary Cholesterol Recommendations

When it comes to dietary cholesterol, the American Heart Association recommends a ceiling of no more than 300 milligrams (mg) per day. Your liver produces an estimated range of 800 to 1,500 mg of cholesterol per day, and this is under genetic control. 

Your liver needs cholesterol for bile, sex hormones, and vitamin D. According to Professor Anding, since the liver naturally produces so much cholesterol, there is little need to obtain cholesterol through your diet.  

We obtain—on average—25 mg of cholesterol per ounce of meat. Thus, many experts are recommending a more plant-based diet. Dietary cholesterol can raise blood cholesterol and in a much less predictable fashion than saturated fat. Organ meats are typically high in cholesterol, as is egg yolk. 

Shellfish—depending on the type—can have around 100 mg of cholesterol per half cup serving. Shellfish, however, is low in saturated fat and thus may be a better choice than other animal products if you need to keep your cholesterol in check.

Insulin’s Role

The hormone insulin can also contribute to heart disease. Insulin resistance as seen in type 2 diabetes and metabolic syndrome can result in your body making more insulin than it needs. 

Because your body is resistant to insulin, it produces an excess, and many experts view elevated levels of insulin in your blood as an independent risk factor for heart disease. Insulin is an anabolic hormone, which means that it increases nutrient transfer from the blood to the cells, where it can be stored as energy and fat. 

Increased insulin resistance and output may be associated with an increased risk of heart disease. Obesity contributes to insulin resistance, which is why it’s also linked with type 2 diabetes.

Insulin is anabolic for carbohydrates, meaning that it’s needed to transfer carbohydrates from the blood to the cells where it can be used. It’s also anabolic for protein, fat, sodium, potassium, phosphorus, and fluid, so it is a major powerhouse in terms of getting nutrients inside the cell. 

Measuring Your Triglycerides

High insulin levels can facilitate fat synthesis because the more of this anabolic hormone you have, the more insulin you make and the more fat storage you promote. High insulin levels increase triglycerides, a type of fat found in your blood.

This chain reaction occurs because triglycerides are the way we store excess calories. If you’re producing a lot of insulin, more of your calories will go into storage. 

Some recent evidence suggests that the best way to measure triglycerides via a blood test should not be after fasting but rather after a meal. Doing so will help you determine how your body processes that food, what your triglycerides are in the presence of that extra insulin, and how insulin can transfer the nutrients into your cells. If your triglycerides are high, it may signal that you have an issue with insulin metabolism. 

Finally, fiber plays an essential role in a heart-healthy lifestyle. Fiber slows the rate of glucose digestion after a meal. A high-fiber meal will stimulate more insulin than a low-fiber meal. This is because the amount of food reaching the blood is delayed with that high-fiber meal, and fiber binds to bile. Therefore, fiber will help to keep your blood sugar levels balanced and, by extension, can prevent or alleviate heart disease. 

This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.

Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.