Phytosterols Deciphered

Phytosterols have been a player in the heart health scene for many years, yet few people know of or understand these plant-based compounds.

What are Phytosterols?

Plant sterols are found in most plant-based foods.  However, it is difficult to eat the amount needed for health benefits with a typical dietary pattern.  As a result, most phytosterols are concentrated from vegetable oils or tall oil from pine trees.  More than 40 different plant sterols have been identified and the most abundant include sitosterol, campesterol and stigmasterol. These three compounds comprise up to 98% of the total phytosterols in certain seeds and vegetable oils, as well as the phytosterols concentrated from pine trees.  Plant stanols (a fully saturated form of the plant sterol) may also occur naturally in plants, but in much lower amounts than sterols. Most plant stanols are produced by conversion of plant sterols. The common forms include sitostanol and campestanol.

Both of these sterol compounds, plant sterols and stanols, can be added to food for health benefits.   The FDA and other global regulatory authorities have recognized the cholesterol-lowering effect of plant sterols and stanols from vegetable oil and tall oil. Within the United States, the health claim for phytosterols and coronary heart disease (CHD) risk requires a concentration of at least 80% beta-sitosterol, campesterol, stigmasterol, sitostanol, and/or campestanol (combined weight) in the phytosterol ingredient [75 FR 76525].

Phytosterols and Heart Health

Many factors may affect blood cholesterol levels such as diet, exercise, and genetics.  The effect of phytosterols on blood cholesterol levels have been evaluated in more than 100 human intervention trials including various populations such as groups on cholesterol-lowering medications; with diabetes; with normal and elevated cholesterol; and with familial hypercholesterolemia.  Studies have consistently demonstrated the ability of a diet supplemented with approximately 2 g/day phytosterols to reduce low-density lipoprotein (LDL) cholesterol, a major risk factor for coronary heart disease (CHD), by 8-15% in populations with normal and elevated cholesterol levels (FDA 2010) and (European Food Safety Authority - EFSA 2008a, 2008b, 2009a, 2009b). Numerous global regulatory authorities, cholesterol educational coalitions, and independent researchers have reviewed the available clinical studies and concluded that dietary intake of phytosterols is safe and effective for lowering LDL cholesterol. 

FDA Health Claim for Phytosterols in the United States

Within the United States, the criteria for the phytosterol health claim has shifted in recent years.  The following citations will help clarify the current claims and food product profile needed to make the approved FDA phytosterol health claim.

Plant Sterol Health Claim (US)   21 CFR  101.83               

Foods containing at least 0.65g of sterol esters (0.4g plant sterols) per serving eaten twice a day with meals for a daily intake of at least 1.3g sterol esters (0.8g plant sterols), as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.  A serving of (name of food) provides __grams of plant sterols".

To qualify for this health claim, the product must be:

However, in December of 2010, FDA issued a proposed rule (www.gpo.gov/fdsys/pkg/FR-2010-12-08/pdf/2010-30386.pdf) that would amend the sterols health-claim model wording to communicate a higher recommended intake level based on a current review of the science. The new proposed model health claims noted in the proposed rule are the following:

(1)"Foods containing at least 0.5 grams per serving of phytosterols (plant sterols) eaten with meals or snack for a daily total intake of 2 grams as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.  A serving of (name of the food) supplies __grams of phytosterols (plant sterols)."

                                OR

(2) Diets low in saturated fat and cholesterol that include 2 grams per day of phytosterols (plant sterols) eaten with meals or snacks may reduce the risk of heart disease.  A serving of (name of food) supplies _grams of phytosterols (plant sterols)."

The same guidelines around total fat, saturated fat, cholesterol and the Jelly Bean Rule" would apply to this new claim.

As of today, FDA has not finalized the revised proposed rule for the phytosterol health claim.  They have communicated via Federal Register notice that products which meet the current or

the proposed levels for plant sterols (and associated requirements for the claim) can continue until a final decision is made (then all products must comply with the final rule).  In addition, the 2003 Letter of Enforcement Discretion allows the health claim to be used on most foods and dietary supplements meeting the nutrient content guidelines.  This will also continue until publication of a final rule.

People have choices to make as they evaluate their overall health profile.  Diet, exercise and genetics play a major role in heart health, and, for some populations with elevated LDL cholesterol levels, an increased dietary intake of phytosterols may be a safe and effective way of lowering LDL cholesterol and reducing their risk of coronary heart disease. 

Food Product Design offers more about plant sterols and stanols and ingredients that comprise functional foods.

Julie Paul, R.D., is Scientific and Regulatory Affairs Senior Scientist NA, for Cargill, Wayzata, MN. Julie Paul is a Registered Dietitian and regulatory expert with an emphasis on consumer product labeling. She has worked in this capacity for multiple large food companies over the last ten-plus years.