1.1. Origin and Composition
Rose hip is a term used to refer to the extracts produced from the fruits of rose plants (genus Rosa), with most dietary supplements being derived specifically from Rosa canina or the 'dog rose'. The 'fruit' of the rose (Cynosbati fructus or fructus cynosbati) is more correctly termed a pseudofruit or accessory fruit due to it not being the ovary of the plant, and the seeds within the fruit are usually discarded during processing of rose hip supplements.
The overall 'rose hip' (accessory fruit) ranges in weight from 1.25-3.25g of which 71% is the usable pericarp which contains around 75% water content and a fatty acid content of 1.78%. The fatty acid content is mostly α-linolenic acid at 40.5% of total fatty acids, followed by palmitic (16.4%) and linolenic (16%) acids with trace amounts of other monounsaturated and saturated fatty acids.
The pericarp tends to be the part used medicinally for anti-rheumatic purposes; specifically, 2-5g of the accessory fruit is ground up and a water extraction (tea) is brewed to be drank up to four times daily.
The rose hip differs from Rose Essential Oil which is derived from flowers and usually from other species of rose.
Rose hip is a term used to refer to extracts from the fruits of rose plants, usually Rosa canina. The water extracts have traditionally been used as a tea to treat rheumatic diseases such as arthritis, in addition to being used for the treatment of diabetes.
Rose hip (dried powder extract when components are quantified, unless otherwise specified) tends to contain:
Galactolipids, of which the major one is 1,2-di-O-α-linolenoyl-3-O-β-D-galactopyranosyl-sn-glycerol (DLGG, although GOPO is sometimes used synonymously) at around 2.5mg per 10g of a powdered water extract
Procyanidins, with some reported to be larger than trimers and are glycosides (procyanidins usually being aglycones)
trans-Tiliroside (Acetylated Kaempferol glycoside) at more than 0.1% of the water extract
Flavonoids including Apigenin, eriodictyol, Quercetin and various glycones including rutin, and phlorizin
Triterpenoids including oleanolic acid, Ursolic Acid, and betulinic acid
Tannins including Pedunculagin and methyl gallate rutinoside
Vitamin C between 112.2mg/100g and 360.22mg/100g (0.12-0.36%) depending on biotype with highest reported content being 1,300mg/100g (1.3%) and lowest being 40-47mg/100g in the fresh pulp
Carotenoids including neochrome, Lutein, zeaxanthin, rubixanthin, lycopene, and β,β-carotene
Dietary minerals such as sodium (3.97-4.67mg/kg), potassium (up to 1.16% of the tea and 0.89-1.02% of the dry fruit weight), Calcium (18mg/kg or up to 0.6% of the tea), Magnesium (1,909mg/kg), Iron (267mg/kg), Aluminum (157mg/kg), Manganese (244mg/kg), Zinc (22mg/kg), Copper (5mg/kg), Selenium (59mg/kg), Barium (47mg/kg), Nickel (2.9mg/kg), Chromium (900µg/kg), and Cobalt (400µg/kg)
Despite being thought to be the active component, DLGG is prominent in a variety of food products although rosehip does not appear to be an abnormally high source relative to others. Among citrus food products, rose hip pseudofruits appear to have relatively superior vitamin C content, which is thought to underlie some of the medicinal uses of the plant. While the vitamin C content correlates positively with overall polyphenol content, it should be noted that among rosa pseudofruit species that canina tends to have a lower average vitamin C content than other species such as villosa and drumosa, with the polyphenol content also being lower in this species and relative to other medicinal herbs.
The bioactives found in rose hip (beyond the macronutrient composition) are divided between polyphenolic compounds, triterpenoids such as ursolic acid, and the galactolipids such as GOPO. Although GOPO is usually credited with being the active ingredient, the other compounds may also contribute to the efficacy of this pseudofruit and no bioactive (except perhaps some of the procyanidin glycosides) seem to be unique to rose hip.
2.1. Known Drug Interactions
One study has noted that a fruit tea containing rose hip and Hibiscus sabdariffa (in a 60:40 ratio) showed a false positive on a digoxin assay, thought to be related to the individual flavonoids in the tea as this false positive was also noted with isolated delphinidin and Cyanidin as well as pure Quercetin.
A case study has noted that a fruit tea which contains rose hip may show as a false positive on some digoxin assays, thought to be related to the anthocyanin content.
3.1. Blood Pressure
In obese people given 40g of rose hip powder as a beverage daily for six weeks, supplementation of rose hip was associated with a 3.4% reduction in systolic blood pressure relative to placebo with no significant influence on diastolic blood pressure.
A mild reduction in blood pressure has been noted with rose hip supplementation.
Supplementation of 40g rose hip powder via a beverage for six weeks in obese people was noted to significantly reduce total cholesterol and LDL cholesterol by 4.9% and 6% respectively. When only considering individuals not on statin therapy, the magnitude slightly increased to 5.5% and 8.6%. No changes were observed in HDL-C in this study.
A reduction in LDL cholesterol has been noted with supplementation of rose hip, although HDL cholesterol seems unaffected.
4Interactions with Glucose Metabolism
4.1. Blood Glucose
Supplementation of 40g rose hip daily for six weeks in obese persons failed to influence either fasting or postprandial glucose concentrations, with fasting insulin also unaffected.
Rose hip supplementation does not seem to modify blood glucose concentrations either in the presence of food or without.
In obese individuals, some of which were insulin resistant but none of which were diabetic, 40g of rose hip powder via a beverage (which contained sugars) daily for six weeks failed to influence biomarkers of glucose metabolism such as HbA1c relative to placebo drink.
HbA1c has been noted to be unaffected by supplementation of rose hip extract.
When tested in vitro, both rose hip extract (62.5-250μg/mL; estimated IC50 of 185.1μg/mL) and the flavonoid tilirioside (15.6-62.5μg/mL; estimated IC50 of 34.3μg/mL) attenuated lipid accumulation in adipose tissue in a concentration-dependent manner, although both were less potent than the control of 1μg/mL Berberine (chloride) which fully suppressed adipogenesis.
When rose hip extract was added at 1% of a mouse diet for eight weeks in conjunction with a high-fat diet, there was a nonsignificant trend to reduce liver lipids (54.3%) and triglycerides (32.5%), and expression of PPARγ (a protein regulating fat cell proliferation and differentiation) appeared to be reduced 33.8% relative to high-fat control, which may explain rose hip's ability to attenuate fat accumulation.
Although the bioactive is unknown, it appears that rose hip supplementation may suppress levels of PPARγ which positively influences fat cell proliferation and differentiation. This is thought to underlie possible antiobese properties of rose hip.
Obese, diabetic mice on a high-fat diet along with 100mg/kg tiliroside, a compound in rose hip which is thought to reduce fat accumulation (although it may not be the only active component), failed to reduce body fat gain over three weeks despite having bioactivity in the liver. Other studies in non-diabetic mice have found benefits with consumption of either the whole fruit or seed (but not pericarp only) extracts at up to 50mg/kg over two weeks and ten weeks of 33% rose hip powder.
One single-blind, placebo-controlled human trial in people whose BMI was between 25 and 30 for 12 weeks found that, in those taking 100 mg rose hip extract containing at least 0.1% of tiliroside, abdominal visceral fat area decreased by 9.23 cm2 (versus a 3.24 cm2 increase in the placebo group) and bodyweight decreased by 1.4 kg (versus a 0.26 kg decrease in those taking placebo). There was no change in average daily caloric intake between the two groups as measured by food diaries. Another study using weight as a secondary measurement failed to find any weight loss effect in obese persons given 40g of rose hip daily over six weeks.
Mouse evidence has shown an antiobese effect of rose hip when coingested with a diet designed to induce fat gain. The limited evidence in humans so far has had mixed results.
6.1. Collagen and Joints
When testing galactolipids from rose hip in vitro in SW1353 (chondrosarcoma) and primary chondrocytes which are stimulated by IL-1β (an inflammatory cytokine known to promote degradation of these cartilage cells), the presence of the galactolipid GLGPG (9.7µg/mL) attenuated the subsequent release of MMP1, 3, and 13 (proteins which cleave type-II collagen) but was less effective than 250µg/mL of rose hip powder. There were some suppressive effects on ADAMTS-4 and 5 (which cleave proteoglycans) although to a lesser degree. LIF, another protein stimulated by IL-1β which is involved in the catabolism of cartilage during osteoarthritis, was also reduced with coincubation of rose hip extract or GLGPG.
The above actions are thought to be secondary to reducing the ability of IL-1β to stimulate NF-kB, which has been noted with rose hip in vitro (10μg/mL), and which also ablated the ability of IL-1β to reduce chondrocyte proliferation.
Rose hip appears to be able to reduce the activity of various proteins involved in the breakdown of collagen in vitro by interfering with the actions of circulating cytokines (such as IL-1β) which activate these proteins. This interference is thought to stem from an inhibitory effect on NF-kB, which mediates the ability of IL-1β to induce the activity of the catabolic proteins.
One preliminary study with no control group noted that consumption of 10g of rose hip powder for four weeks in a small group of people with physical labour jobs was able to reduce subjective joint discomfort, the degree of which was not stated. Another randomized study with a control group in people with self-reported problems walking due to knee problems (no etiology of these problems was used in the selection criteria) found that 2.25 g rose hip powder over 12 weeks improved improved gait analysis measurements as well as improved knee flexion during walking.
Preliminary and limited evidence suggests that rose hip may improve joint discomfort and improve knee mobility during walking, although more research is needed.
C-reactive protein has been noted to be reduced following ingestion of under 45g of rose hip powder over the course of a month in two preliminary studies in otherwise healthy people without signs of cardiovascular disease, although a controlled trial using 10.5g of rose hip powder in both persons with rheumatoid arthritis and normal controls failed to find any benefit with supplementation, and another study using 5g rose hip for six months only noted a nonsignificant trend to reduce C-reactive protein, although symptom relief was noted.
Rose hip powder from Rosa canina at the dosage of 5,000mg in two divided daily doses for three months in people with knee or hip osteoarthritis noted benefits with supplementation, where overall WOMAC scores (a rating scale for joint symptoms) declined 13% relative to no change seen in placebo, and 82% of people reported some benefit with rose hip (versus 49% with placebo). This study noted more benefits seen after three months than three weeks (where only pain was reduced) and that paracetamol usage declined 40% when patients were supplementing with rose hip. Benefits have been noted with rose hip elsewhere where supplementation of the same dose for four months resulted in self-reported improvements in pain in 64.6% of users (35.4% of placebo reporting such), although a whole-group benefit was not calcuated and pain was assessed on a 1-4 rating scale. One other study using 5g a day has also noted time-dependent benefits, although in this case it was due to using rose hip supplementation for three months prior to a placebo therapy (due to the crossover design of the study), causing prolonged benefits during placebo administration.
Rose hip supplementation at 2,500mg twice daily appears to provide mild benefits to osteoarthritis symptoms when compared to placebo based on preliminary evidence, and the benefits appear to be more significant with longer time of administration.
6.3. Rheumatoid Arthritis
A study using 10.5g of rose hip powder daily for one month failed to note any benefits to rheumatoid arthritis relative to baseline (no placebo group used) as assessed by HAQ and VAS scores for pain, although elsewhere 5g of the extract has shown benefit to people with rheumatoid arthritis after six months in certain symptom scales but not others, but no benefit after three months.
There may be some benefits with long-term rose hip ingestion in persons with rheumatoid arthritis that are not seen with short term usage, and this benefit may occur at lower doses of rose hip supplementation, although the evidence is mixed at this point in time.
7Inflammation and Immunology
The migration of polymorphonuclear leukocytes is known to play a pathological role in forms of arthritis (both osteoarthritis and rheumatoid) by promoting inflammatory and oxidative signalling, and rose hip (water extract) has been noted to reduce this migration at concentrations of 100µg/mL up to 500µg/mL. This is thought to be related to the GOPO content, which has shown efficacy on its own in vitro.
Oral supplementation of 10g of the powder in otherwise healthy men over one month has been noted to reduce chemotaxis by up to 50% relative to no treatment, with a higher dose (45g) showing slightly more efficacy (up to 65%), Similar results have been noted elsewhere.
Migration of polymorphonuclear leukocytes, which are involved in the pathology of arthritic diseases, appears to be reduced with both in vitro application and oral ingestion of rose hip extracts.
8Peripheral Organ Systems
Components of rose hip extract may modulate PPAR proteins, as both tiliroside and its aglycone Kaempferol have been shown to suppress the activity of PPARγ secondary to activation of AMPK, since activation of this protein has not only been noted with tiliroside in vivo but it also phosphorylates and inactivates PPARγ while reducing PPAR mRNA transcription. Tiliroside has also been noted to activate PPARα, which may increase the rate of fatty acid oxidation in the liver.
Oral ingestion of 1% rose hip extract given with a high-fat diet to mice over eight weeks has been noted to trend (nonsignificantly) to reduce hepatic accumulation of lipids (54.3%) and triglycerides (32.5%) Elsewhere 100mg/kg of pure tiliroside to similar mice for three weeks significantly suppressed triglyceride accumulation by 34%, although it did not suppress body fat gain or alter metabolic rate (although the respitatory quotient, a biomarker of fatty acid consumption, was increased relative to control).
It has been noted in mice that rose hip supplementation is able to reduce lipid and triglyceride accumulation in the liver, suggesting possible benefits to the development of fatty liver. There is currently no human evidence for this claim (which, at times, showed interspecies differences favoring benefits in mice relative to humans).
9Interactions with Aesthetics
One study with healthy nonsmoking men and women ages 35-65 found an improvement in crow's feet wrinkles, forehead skin moisture, and cheek skin elasticity when supplemented with 3 g oral rose hip powder daily. The amount of improvement was similar to 4 mg astaxanthin, an antioxidant with some cosmetic benefits.
10Sexuality and Pregnancy
A dietary supplement containing rose hip (50mg; confounded with 200mg of both L-arginine and L-citrulline along with 20mg Pycnogenol) has been noted to improve sexual function of otherwise healthy women as assessed by the Female Sexual Function Index (FSFI) in a time-dependent manner over eight weeks. The 31% increase in the placebo group was outperformed by an 88% (four weeks) and 126% (eight weeks) improvement with supplementation. This compound formulation has also shown efficacy in postmenopausal women (two entries for the same study,) but due to the low dose of rose hip relative to a dose of pycnogenol known to be effective in isolation, it is thought that rose hip is not the active component.
No good evidence at this time to suggest benefits of rose hip supplementation to libido and sexual well-being, as the only evidence available is confounded by known beneficial agents.
Supplementation of up to 5,000mg rose hip powder daily for three months failed to have any significant side-effects relative to placebo in people with osteoarthritis.
Gastrointestinal side-effects such as diarrhea, loose stools, and persistent constipation have occurred with ingestion of 40g rose hip extract via a beverage taken daily for six weeks.
There do not appear to be any known side-effects associated with moderate rose hip supplementation, although higher doses appear to be associated with gastrointestinal side effects (diarrhea, loose stools, persistent constipation).