Module 8: Natural Products in Complementary and Alternative Medicine


Many Americans are now pursuing Complementary and Alternative Medicine (CAM) as an alternative or supplement to conventional medicine. A 2007 National Health Interview Survey (NHIS) showed that approximately 38% of adults in America use CAM.(1)

The National Center for Complementary and Alternative Medicine (NCCAM) defines CAM as “a group of diverse medical and health care systems, practices, and products that are not generally considered part of conventional medicine.”(2) Complementary medicine is used in addition to conventional medicine, while alternative medicine replaces conventional medicine. The combination of CAM and conventional medical practices is known as integrated medicine. However, overall efficacy of CAM is still in debate, according to NCCAM, as there are no rigorous, well-designed clinical trials for CAM therapies.(3) One factor precluding carefully controlled clinical trials is the expense of these studies. Research trials for conventional drugs are funded by companies that develop and sell drugs, but fewer resources are available to support trials of CAM.

There are many different components within CAM, including natural practices, mind and body medicine, and manipulative and body-based practices. Mind and body medicine improves health by focusing on the interaction between mind, body, and behavior. Examples include meditation, acupuncture, yoga, qi gong, and tai chi. Manipulative and body-based medicine focus on the bodily structures and systems. Examples include spinal manipulation (performed by chiropractors to slightly move a joint of the spine) and massage therapy (in which therapists manipulate soft tissues to relieve pain, reduce stress, address anxiety, and improve health).(4)

Natural Products

Natural products related to CAM include herbal medicines (also called botanicals), vitamins, minerals, and probiotics . These types of natural products are becoming more popular among Americans: 17.7% of American adults reported using non-vitamin/non-mineral natural products in 2007.(5) A popular product among adults in 2007 was oil/omega 3s, used by 37.4% of all adults who reported using natural products. Popular products used in 2007 for children were Echinacea (used by 37.2% of children who reported using natural products) and fish oil/omega 3s (30.5% of children).(6) Details of these products and other commonly discussed natural products follow.


Probiotics are live microorganisms, usually bacteria, that are similar to beneficial microorganisms found in the human gut. The most common types of these “good bacteria,” Lactobacilli and Bifidobacteria, are available to consumers in the form of dietary supplements and foods (such as yogurt). Little evidence supports the claim that probiotics help prevent colds.(7) However, strong evidence supports the use of probiotics to slow the growth of certain cancerous tumors.(8) A study of 10 colorectal cancer patients and 20 healthy persons showed that colorectal patients have deteriorated intestinal environments compared to the healthy controls, but that intestinal conditions improved when probiotics were taken, suggesting that probiotics may prevent colorectal cancer.(9) A different study showed that pigs given vaccines and probiotics have better immune systems than pigs given only vaccines.(10) This knowledge helps researchers understand how to offer safer and more effective rotavirus vaccines in humans. However, both studies noted that more research on the mechanisms behind the health effects of probiotics must be conducted.

Oil/omega 3s

Omega-3 fatty acids are naturally found in fish, plant, and nut oils, and have also been made into dietary supplements. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which have been proven to lower triglycerides, slow the buildup of atherosclerotic plaques (hardening of the artery walls), lower blood pressure, and reduce risk of death, heart attack, and dangerous abnormal heart beats due to cardiovascular disease.(11) More specifically, an analysis of 17 clinical studies of the use of fish oil supplements showed that taking three or more grams of fish oil daily significantly reduces blood pressure for people with untreated hypertension.(12) One clinical study found that overweight, mildly hyperlipidemic men who took four grams of purified DHA per day had lower blood pressure (BP) than did those who took the placebo, olive oil capsules. The study concluded: “Relative to the placebo group, 24-hour BP fell 5.8/3.3 (systolic/diastolic) mm Hg and daytime BP fell 3.5/2.0 mm Hg with DHA.”(13) Furthermore, fish oil is effective in reducing high triglyceride levels by 20 to 50%. One fish oil supplement, Lovaza, is now FDA-approved for use to lower triglycerides.(14)


Echinacea is a flower found in the Midwestern region of North America and is widely used to treat, prevent, or shorten the duration of colds and to stimulate the immune system to fight infections. The parts of the Echinacea flower that grow above ground can be used fresh or dried to make teas, juice, and extracts. Health effects of Echinacea are uncertain. Two NCCAM-funded studies did not find any health benefits from Echinacea (either as Echinacea purpurea in a fresh-pressed juice or a mixture of Echinacea angustifolia root and Echinacea purpurea root and herb). Other studies have shown that Echinacea may help treat upper respiratory infections.(15) Different results have been observed because each study uses different methods of preparation. Therefore, Medline rates Echinacea as “possibly effective” for treating the common cold (but not effective in preventing it).


Acai is a palm tree found in the northern regions of South America. The acai palm tree produces reddish-purple berries that are commonly used as medicine. Acai is now widely marketed in America as a “superfood,” because it is claimed to have weight-loss and anti-aging properties. However, no definitive evidence from clinical trials shows human health benefits of acai berries. Laboratory studies of acai berries do support their antioxidant properties (antioxidants are substances that protect cells from damaging effects of chemical reactions with oxygen). A 2008 study showed that antioxidants in a juice blend (MonaVie Active) that contains acai as a primary ingredient protected cells from oxidative damage.(16) Still, no published studies support claims that acai supplements alone promote weight loss.(17)


Soy, a plant in the pea family, is also marketed as a “superfood,” because it is reputed to lower cholesterol levels.(18) According to the FDA, 25 grams per day of soy protein, in addition to a diet low in saturated fat and cholesterol, may reduce the risk of heart disease by lowering levels of LDL (“bad” cholesterol).(19)(20) A 2006 study found that in the majority of 22 randomized trials, isolated soy protein with isoflavones decreased LDL concentrations.(21)

Green Tea

Green tea is a product made from the Camellia sinensis plant and can be prepared as a beverage or as a medicine. Green tea is used to increase mental alertness, due to its caffeine content, and is purported to facilitate weight loss, though no evidence supports this claim.(22) Green tea is, however, rated as “possibly effective” at preventing certain types of cancer, including bladder, esophageal, ovarian, and pancreatic cancer. One study reported that women who drank more than two cups of green tea daily had a 46% lower risk of developing ovarian cancer compared to women who did not drink green tea.(23)


(1) NIH. "What Is Complementary and Alternative Medicine?" National Center for Complementary and Alternative Medicine (NCCAM). National Institutes of Health, 6 Feb. 2012.

(2) Ibid.

(3) Ibid.

(4) Ibid.

(5) Ibid.

(6) Ibid.

(7) "Two Studies Explore the Potential Health Benefits of Probiotics." NCCAM. National Institutes of Health, 4 July 2008.

(8) Ibid.

(9) Ohara T, Yoshino K, Kitajima M. Possibility of Preventing Colorectal Carcinogenesis with Probiotics. Hepatogastroenterology, 2010 Nov-Dec;57(104):1411-5.

(10) "Two Studies Explore the Potential Health Benefits of Probiotics." NCCAM. National Institutes of Health, 4 July 2008.

(11) Mayo Clinic. "Omega-3 Fatty Acids, Fish Oil, Alpha-linolenic Acid." Mayo Foundation for Medical Education and Research, 01 Oct. 2011.

(12) "Omega-3 Fatty Acids, Fish Oil, Alpha-linolenic Acid.” University of Maryland Medical Center, 2011.

(13) Mori TA, Bao DQ, Burke V, Puddey IB, Beilin LJ. Docosahexaenoic acid but not eicosapentaenoic acid lowers ambulatory blood pressure and heart rate in humans. Hypertension 1999;34:252–60.

(14) "Fish Oil: MedlinePlus Supplements." U.S. National Library of Medicine, 10 Dec. 2011.

(15) "Echinacea." NCCAM. National Institutes of Health, July 2010.

(16) Jensen GS. Wu X. Patterson KM, et al. In vitro and in vivo antioxidant and anti-inflammatory capacities of an antioxidant-rich fruit and berry juice blend. Results of a pilot and randomized, double-blind, placebo-controlled, crossover study. J Agric Food Chem. 2008;56:8326–8333. 

(17) NIH. "Acai" NCCAM. National Institutes of Health, April 2011.

(18) Feature, Susan SeligerWebMD. "'Superfoods' Everyone Needs: Blueberries, Tea, Salmon, & More."

(19) "Soy." U.S. National Library of Medicine.

(20) NIH. "Soy" NCCAM. National Institutes of Health, Oct 2007.

(21) F. M. Sacks, A. Lichtenstein, L. Van Horn, W. Harris, P. Kris-Etherton, and M. Winston, “Soy protein, isoflavones,
and cardiovascular health: An American Heart Association Science Advisory for professionals from the Nutrition Committee,” Circulation, vol. 113, no. 7, pp. 1034–1044, 2006.

(22) NIH. "Green Tea" NCCAM. National Institutes of Health, July 2010.

(23) "Green Tea." U.S. National Library of Medicine, 26 Oct. 2011.