Olestra
Nat Cooper

We will see how researchers used these simple chemical concepts to invent and develop olestra and we will use these principles ourselves to evaluate and decide on nutritional issues

Like Dissolves Like
Carotenoids
Harvard and Carotenoids

Like Dissolves Like: Probably the greatest issue concerning olestra is the interaction of olestra with fat soluble vitamins and nutrients. This interaction is based on one of the most fundamental and important chemical principles, that like substances dissolve each other.

Since olestra is a fat in all respects except its digestibility, other fat soluble or lipophilic substances will dissolve in the olestra. This means that for all of these fat soluble vitamins, nutrients and drugs, olestra can have a leaching effect.  If a person ate olestra and the fat soluble vitamins, the vitamins might dissolve in the olestra and be removed, unabsorbed.   This might possibly reduce the amount of the particular substance that is absorbed by the body.

This dissolving of a food component into the olestra is known as partitioning and depends on three key factors:

• The degree of fat solubility- some substances are more soluble than others
• The amount of olestra- the more olestra that is present in the gastrointestinal tract, the greater the amount of lipophilic substance that can dissolve into the olestra
• The time between consumption- olestra stays in the gastrointestinal tract only about two hours so any nutrient absorption will occur only during that time period

With these factors in mind, Procter & Gamble designed numerous studies involving a variety of drugs, vitamins, and nutrients.

They selected drugs that would be in fairly widespread use, had a wide range of solubilities, and were available as radiolabeled versions. After many experiments both with rats and in human clinical trials, the FDA concluded that Procter & Gambles studies were sufficient and that the drug-food interactions were minimal and similar to the interactions found with many other food and drug combinations.

To assess the effects of olestra on fat soluble vitamins, Procter & Gamble conducted five animal and five human trials that had a variety of experimental designs. The vitamins and mineral studied included vitamins A, D, E, K, folate, zinc, iron, B₁₂, beta-carotene and total carotenoids. These studies did show that some of the fat-soluble vitamins do partition into olestra. The FDA and Procter & Gamble in many cases disagreed on the potential harm from this, especially when it is common for some of the snack consumption to occur at times between meals, but in the end Procter & Gamble added the vitamins A, D, E, and K to the olestra in order to prevent any additional partitioning of these vitamins from food in the gastrointestinal tract.

The absorption of many water soluble minerals such as zinc, folate and iron, B₁₂, calcium was shown not to be affected by olestra so these were not added to the olestra.

Carotenoids:   The issue of beta-carotene and total carotenoids is a bit more complex.

Carotenoids are the yellow orange and red pigments that are present in many of the commonly eaten fruits and vegetables. These classes of compounds are thought to have some effect on a lower incidence of cancer. In the years since the benefits of carotenoids were first hypothesized, studies have been conducted specifically to research the action and possible benefits of a single carotenoid, beta-carotene.

Unfortunately, these studies have not indicated clear cause- effect relationships between consumption and lower cancer incidence. While many do believe that the beta and other carotenes are beneficial, It may be that there are other compounds in the fruits and vegetables that are beneficial. It also may be that people who consume lots of fruits and vegetables also have healthier lifestyles and that this lifestyle is responsible for the lower cancer incidence.

In studies designed to maximize the interaction between olestra and the various carotenoid compounds, participants were consuming olestra at every meal while they also consumed carotenoid containing foods. These results indicated that some reduction in the amounts of carotenoids absorbed by the participants did occur. Other studies, designed to mimic "real life" snacking conditions, where the snacking did not always occur at the same times as the carotenoid consumption, demonstrated a minimal interaction between the carotenoids and olestra. The mixed results of these studies, coupled with the uncertainty regarding the exact benefits of the carotenoid compounds, led to the FDA not requiring supplementation of olestra with any carotenes. This is an area of concern and controversy regarding olestra with studies and discussion continuing.

Harvard and Carotenoids: In 1996 The Harvard School of Public Health hosted a workshop addressing the issues of carotenoid benefits, and the concerns regarding olestra and this potentially important class of compounds. Dr. Walter C. Willett thanked the CSPI for alerting the FDA to the potential problem of Olestra drawing carotenoids from the system based on their diligence in reviewing P&G's research.

The conference developed no answers but focused researchers on the problem of evaluating conflicting scientific factors in any human health scenario. Dr. Willlett drew one critical conflict. Perhaps we need to add carotenoids to the diet to offset the amount extrcted by Olestra. But if we unintentionally add too much of the substances, harm may be done. And physicians guide themselves by the words of Hippocrates, "Do no harm!".

We have seen how these many vitamin and nutrient studies led to the supplementation of olestra in some cases, and non supplementation in others. The concerns regarding this aspect of olestra are among the factors you will weigh as you look at the Case Discussion. For now though, return to the Olestra Concept Map to look at another major issue- is olestra effective as a fat and calorie reducing aid.