By: Lila Ahmed, Pharm.D. Candidate c/o 2013
Whether you wish to admit it or not, all of us have watched or at least heard of the Dr. Oz Show. I am sure that many of us encounter patients in the pharmacy who say, “I saw this on Dr. Oz; where could I find it?” or “Dr. Oz says this pill is good for my cholesterol.” It makes you wonder how accurate these recommendations are and if people should take advice from a television show. Yet, is there evidence to support the use of these supplements?
One of Dr. Oz’s most recent episodes discussed weight loss and targeted specific problem areas for five body types. Just one of the many “fat burner” supplements mentioned was raspberry ketones.1
What are they?
Raspberry ketones, chemical name 4-(4-hydroxyphenyl)butan-2-one, are the primary aromatic compounds found in red raspberries. They are primarily used in perfumes and food additives to provide a fruity odor. The raspberry ketone’s chemical structure is similar to that of capsaicin and synephrine, both of which have lipolytic activity and are associated with weight loss.1-4
How do they work?
Raspberry ketones secrete adiponectin, which, according to Dr. Oz, “naturally tricks your body into acting like it’s thin.” Adiponectin is a protein used by the body to regulate metabolism. Higher levels are associated with fewer fat stores. Raspberry ketones cause the fat within your cells to break up more effectively, helping your body burn fat faster. Scientists who studied the effects of raspberry ketones on mice observed a higher secretion of adiponectin when compared to controls. Researchers also observed that raspberry ketones decreased the amount of fat in the liver and abdominal fat tissues of mice. These compounds also significantly increased norepinephrine-induced lipolysis in some rat fat cells.1,2,4
A Japanese animal study conducted in 2005 evaluated the effects of raspberry ketones on weight loss. Mice were fed high fat diets for six weeks, and then given 0.5%, 1%, or 2% raspberry ketones (in addition to the high fat diet) for an additional five weeks. The results show that raspberry ketones taken with a high fat diet significantly reduce weight gain and increase lipid metabolism by increasing norepinephrine-induced lipolysis. This study concluded that raspberry ketones prevent obesity and fatty liver.5
There is insufficient evidence regarding the safety and side effects associated with raspberry ketones, since they have yet to be studied in humans. However, due to a similarity in chemical structure, it is thought that some stimulant side effects, like those associated with synephrine, may be possible. One case reported heart palpitations and shakiness with the use of raspberry ketones.6
The only interaction associated with raspberry ketones is with warfarin. Raspberry ketones act as CYP 450 3A4 inducers, thereby increasing the metabolism of warfarin in the body. Warfarin doses may need to be increased while taking raspberry ketones in order to maintain therapeutic INR levels.2
According to the Natural Medicines Comprehensive Database, raspberry ketones are used topically for alopecia. Raspberry ketones also act as androgen receptor antagonists, which may have a role in hair growth. They may increase skin insulin-like growth factor (IGF-1) which is involved in promoting hair growth and increasing skin elasticity. In clinical trials, topical raspberry ketones 0.01% applied once a night for five months increased hair growth in 50% of men.2,7,8
Although appropriate doses are not experimentally established, the usual dosage is 100 mg once a day at breakfast. This dose can be titrated up if results are not seen in a reasonable amount of time. According to the Dr. Oz Show, one would have to consume 90 pounds worth of red raspberries in order to get the equivalent concentration of raspberry ketone supplements. Clinically, results may be seen in five to seven days and could last for a few months.1,2
Take Home Message
Raspberry ketones have gained a lot of popularity since their debut on the Dr. Oz Show. As with any advertised weight loss remedy, it is important to use this supplement wisely and not ‘abuse’ it. At the mention of a weight loss medication, people tend to rely solely on the dosage form and ignore the fact that it works best in addition to proper diet and exercise routines. As Dr. Oz emphasized at the end of this episode, raspberry ketones should be used “to get over the hump, and not as a miracle pill.”1
- Raspberry Ketone: what science says. The Dr. Oz Show. http://www.doctoroz.com/videos/miracle-fat-burner-bottle. Updated April 19, 2012. Accessed May 23, 2012.
- De Frambuesa C. Raspberry ketone. Natural Medicines Comprehensive Database. http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?cs=&s=ND&pt=100&id=1262&ds=&name=RASPBERRY+KETONE&lang=0&searchid=34827723. Updated May 22, 2012. Accessed May 23, 2012.
- Koeduka T, Watanabe B, Suzuki S, et al. Characterization of raspberry ketone/zingerone synthase, catalyzing the alpha, beta-hydrogenation of phenylbutenones in raspberry fruits. Biochem Biophys Res Commun. 2011;412(1):104—8.
- Kawada T, Hagihara K I, Iwai K. Effects of capsaicin on lipid metabolism in rats fed a high fat diet. J Nutr 1986; 116: 1272—8.
- Morimoto C, Satoh Y, Hara M, et al. Anti-obese action of raspberry ketone. Life Sci. 2005;77(2):194—204.
- Adverse Event Report. Raspberry Ketone. Natural MedWatch, September 18, 2011.
- Harada N, Okajima K, Narimatsu N, et al. Effect of topical application of raspberry ketone on dermal production of insulin-like growth factor-1 in mice on hair growth and skin elasticity in humans. Growth Horm IGF Res. 2008;18(4):335—44.
- Ogawa Y, Akamatsu M, Hotta Y, et al. Effect of essential oils, such as raspberry ketone and its derivatives, on antiandrogenic activity based on in vitro reporter gene assay. Bioorg Med Chem Lett 2010;20:2111—4.