Does a one-bucket approach for herbal preparations create a problem?

Is it a problem that many consumers and some practitioners do not differentiate between preparations of whole plants (foods) and the concentrated preparations of the constituents isolated from those plants?

I have talked to people who expect similar health benefits from ingesting a curry spiced with turmeric root and capsules containing a purified preparation of curcumin (chemical constituents found in the root). I have also seen scientific papers (metanalysis of clinical studies) that use the terms turmeric and curcumin interchangeably. The problem is that there are differences in the potential benefits from these products. A post on the Arthritis Foundation website declares that “Turmeric Probably Won’t Help Your Arthritis — But Curcumin Might”

Ingesting curries spiced with turmeric root provides general health benefits over a lifetime of consumption. Food preparations provide basic nutrients (proteins, carbohydrates and fats) plus small amounts of pharmacologically active compounds. The most well-known pharmacologically active compounds in turmeric are curcumins. The roots contain roughly 3% curcumins. In contrast, dietary supplement preparations of curcumins, those sold in tablet or capsule form, commonly concentrated to 75% to 97% purity.

We can estimate the amount of curcumin ingested in food and that ingested from purified preparations in capsules or tablets. If a person consumes one teaspoon of turmeric powder (roughly 2,500 mg) in a curry, it will contain about 75 mg of curcumin (3% of 2,500 mg). In contrast, curcumin concentrates (standardized to 75 to 97%) ingested in an amount of 500 mg twice daily (1000 mg/day) provides 750 to 970 mg curcumins. Thuse the supplement delivers roughly 10 times the amount ingested from eating curry.

In addition to the quantity of curcumins, it is important to consider how much of it is absorbed into the body. Curcumins are not water soluble and they are dependent on the matrix surrounding them to facilitate absorption. The absorption of curcumin in turmeric root is facilitated by nutrients and essential oils in the root. In addition, coconut milk and other oils in the curry also aid in the absorption of curcumins.

Curcumin in its concentrated form is not readily absorbed. For this reason, they are often formulated with additional components such as piperine (a component from black pepper) or natural essential oils. Alternatively, concentrated curcumin may be formulated into micelles, emulsions, nanoparticles or liposomes that increase absorption.

The health benefits from ingestion of whole plant (foods) are associated with long-term perspective: a lifestyle dedicated to maintenance of health and disease prevention. Turmeric root ingested in foods is expected to provide general anti-inflammatory and antioxidant effects. In contrast preparations of concentrated curcumin have shown positive effects in clinical studies demonstrating benefits for symptoms of osteoarthritis. Meta-analyses of clinical studies indicate that curcuminoid concentrated can reduce knee pain and stiffness, improve physical function, and reduce the need for rescue medication when compared with placebo. The amounts of curcumin ingested vary with the specific products. Examples are 90-100 mg twice daily for up to 6 months, 500 mg twice daily for 6-12 weeks and 1500 mg daily for 12 weeks.

The safety profile is another consideration when comparing foods to concentrates. The safety of foods is often established over decades or centuries of use. The traditional use of turmeric root in foods spans centuries. In addition, turmeric root is designated as GRAS (Generally Recognized as Safe) for use in food ingredients and as a food additive by the United States Food and Drug Administration.

The safety of concentrated preparations is determined through a battery of in vitro and animal toxicology studies, as well as human clinical studies. Particularly of concern are sensitive populations such as children, pregnant and nursing women. Another consideration is the potential for interactions with pharmaceutical drugs. Curcumin is considered to be quite safe. It has been consumed safely in very high doses of 12 g per day, with only mild adverse events such as diarrhea, headache, rash, and yellow stools. Some preclinical data indicate that co-administration of curcumin with NSAIDs or anticoagulant drugs (such as aspirin) might result in an increased risk of bleeding. But the evidence for this occurring in humans is equivocal.

Both turmeric root as a component of foods and concentrated dietary supplements have a role to play in promoting health. They are not equivalent. One has a role in long-term health promotion and the other is expected to have a more immediate effect.

The Dietary Supplement Health and Education Act (DSHEA) was designed to create a legal category for all herbal products. This means that botanically-derived dietary supplements range from whole plant products to purified constituents. On the plus side, this broad range of products provides consumers, practitioners and manufacturers with choice and flexibility. On the cautionary side, I see confusion in expectations of benefit rising from a lack of distinction between types of products on the market.