**5.2 Can rose hip treatment impact cardiovascular disease, hyperlipidemia, or glucose metabolism?**

Hyperlipidemia and disturbances of glucose metabolism can predispose to cardiovascular disease, which is still a main killer worldwide [65]. A rose hip preparation

based solely on powdered rose hip shells from Chile, administered for 6 weeks, at a daily dose of 40 gram in apple juice, citric acid, and sugar was tested in a randomized, placebo-controlled study.

In the actively treated group, there was a statistically significant 3.4% reduction in systolic blood pressure, while total cholesterol and LDL cholesterol fell by 4.9 and 6.0%, respectively [66]. There was no change in glucose tolerance or markers of inflammation between the treatment and placebo groups. Testing a pure shell liquid product from subspecies *Rosa canina* Lito [60] in a far lower dose (2 gram daily) for 6 months revealed a 4% drop in total cholesterol, when comparing groups. Blood pressure tended to decline because of active treatment. In accordance with these findings, a statistically significant reduction in total cholesterol of 8% and a statistically significant improvement in HDL cholesterol of 2% were observed in two other randomized placebo-controlled clinical trials, while testing a combined shell-seed rose hip powder, of the subspecies Lito, for 3 and 6 months, respectively [60, 67]. The dosage tested was 5 gram of dry rose hip powder daily. Rose hip powder (species and shell/seed content not defined) was shown to exert antiatherosclerotic effects by reducing atherosclerotic plaque formation in mice [68]. At present, there are no studies available focusing on plaque formation in humans. We were not able to find any indication of an impact on glucose metabolism from any subspecies of rose hip—not even when rose hip was tested in the high dose of 40 g of shells [66] or 40 grams of seeds daily (personal communication, Kaj Winther). For that reason, we assume that rose hip does not affect blood glucose levels.

In conclusion: It seems that rose hip can modify lipid metabolism. This can possibly be related to the shells as shell-only powders [62, 66] as well as combined shell/seed powders [60, 67] were able to improve the lipid profile. Such declines were not observed when testing a seed only product in high concentration (personal communication, Kaj Winther). Seeds from rose hip contain high amounts of polyunsaturated fatty acids, among them omega-3 and omega-6. Omega 3 and omega 6 acids [69] possibly supported by certain antioxidants may explain why rose hip powders containing also seeds [59–61] show more anti-inflammatory property than shells-only products [62, 63, 66]. It has not been possible to find any indications of an impact from any version of rose hip on glucose metabolism in humans although a few animal studies look promising.
