Raspberry ketone, a compound found in weight loss supplements, may also make bones stronger, according to an in-vitro study that researchers at Ehime Prefectural University of Health Sciences in Japan published in the Journal of Medicinal Food.
The chemical structure of raspberry ketone is shown on the right. In animal studies raspberry ketone has a slimming effect. Whether the substance has the same effect in humans is not clear. The human equivalent of the effective dose based on amounts used in animal studies would be several grams per day – substantially more than supplement manufacturers advise.
Human studies of slimming supplements containing raspberry ketone have been done, but so far all of these examined supplements that contained raspberry ketone combined with other substances such as caffeine, capsaicin, ginger or Citrus aurantium. [J Int Soc Sports Nutr. 2013 Apr 19;10(1):22.] Supplementation with raspberry ketone alone has never been tested in a human study.
The researchers exposed C3H10T1/2 stem cells to raspberry ketone in test tubes. These stem cells, extracted from bone marrow, can develop into fat cells but also into bone cells in the body. The Japanese hypothesised that raspberry ketone might inhibit the development of stem cells into fat cells but promote the development of the stem cells into bone cells.
In an experiment the Japanese researchers exposed the stem cells to rhBMP-2, a protein that induces stem cells to develop into bone cells. In addition, the researchers exposed the cells to a high concentration of raspberry ketone. The higher the concentration, the more alkaline phosphatase the cells manufacture, an indication that the cells were developing into osteoblasts, bone cells that build up the skeleton.
In another experiment the researchers exposed the stem cells to different concentrations of the vitamin A analogue all-trans-retinoic acid. This compound also stimulates the development of stem cells into bone cells. The more raspberry ketone there was present, the more alkaline phosphatase the cells manufactured – and the greater the bone cell development.
Raspberry ketone had no clear effect on the development of stem cells into fat cells, however, the Japanese discovered.
“Our results indicate that raspberry ketone has the ability to promote the differentiation of C3H10T1/2 stem cells into osteoblasts”, the researchers wrote. “Further investigations of the mechanisms leading to the effect of raspberry ketone on osteoblast differentiation are required.”
The study is interesting for the supplements industry. Women are by far the biggest users of slimming supplements, and most of the weight-loss supplements available currently are caffeine-based. And many studies show that heavy use of caffeine leads to osteoporosis in women. [Am J Epidemiol. 1990 Oct;132(4):675-84.] [Am J Clin Nutr. 1991 Jul;54(1):157-63.] [Am J Clin Nutr. 1994 Oct;60(4):573-8.] Maybe, just maybe, adding raspberry ketone to slimming supplements might not only make these products more effective, but also more bone friendly.
Raspberry ketone promotes the differentiation of C3H10T1/2 stem cells into osteoblasts.
The decrease in the bone mass associated with osteoporosis caused by ovariectomy, aging, and other conditions is accompanied by an increase in bone marrow adipose tissue. The balance between osteoblasts and adipocytes is influenced by a reciprocal relationship. The development of modalities to promote local/systemic bone formation by inhibiting bone marrow adipose tissue is important in the treatment of fractures or metabolic bone diseases such as osteoporosis. In this study, we examined whether raspberry ketone [4-(4-hydroxyphenyl)butan-2-one; RK], which is one of the major aromatic compounds of red raspberry and exhibits anti-obesity action, could promote osteoblast differentiation in C3H10T1/2 stem cells. Confluent C3H10T1/2 stem cells were treated for 6 days with 10-100 ?g/mL of RK in culture medium containing 10?nM all-trans-retinoic acid (ATRA) or 300?ng/mL recombinant human bone morphogenetic protein (rhBMP)-2 protein as an osteoblast-differentiating agent. RK in the presence of ATRA increased alkaline phosphatase (ALP) activity in a dose-dependent manner. RK in the presence of rhBMP-2 also increased ALP activity. RK in the presence of ATRA also increased the levels of mRNAs of osteocalcin, ?1(I) collagen, and TGF-?s (TGF-?1, TGF-?2, and TGF-?3) compared with ATRA only. RK promoted the differentiation of C3H10T1/2 stem cells into osteoblasts. However, RK did not affect the inhibition of early-stage adipocyte differentiation. Our results suggest that RK enhances the differentiation of C3H10T1/2 stem cells into osteoblasts, and it may promote bone formation by an action unrelated to adipocyte differentiation.
PMID: 24404978 [PubMed – indexed for MEDLINE] PMCID: PMC3961782