In last month’s column I reviewed the important research on grape seed extract for maintaining the health of arteries and fine blood vessels (the microcirculation). To some extent, these benefits on the circulatory system might be expected, given what we now know about the value of drinking a moderate amount of red wine. However, I feel that the positive impact of grape seed extract on the microcirculation (see last month’s column) is more or less unique, apart from pine bark (see sidebar page 5).
But the health promoting effects of grape seed extract don’t just stop at the circulation and there are published human studies that back this up. Some of the benefits shown in these trials are quite novel and unique for a dietary supplement. Let’s look at a few examples.
A Japanese study found that a procyanidin (OPC)-rich extract from grape seeds improved chloasma, a facial hyper-pigmentation (or staining) often associated with pregnancy.1
To evaluate the long-term efficacy, a one-year study was undertaken. Grape seed extract (around 200 mg/day of extract) was given to 12 Japanese women with chloasma for 6 months, which was followed by another 5 months of treatment for 11 of those women. The first 6 months of grape seed extract (GSE) intake resulted in slight or substantial improvement in 10 of the 12 women (83 per cent) and the following 5 months saw that improvement maintained in 6 of the 11 women (54 per cent). Objective measurement of the degree of chloasma supported these findings. The authors concluded that the beneficial effects of GSE were maximally achieved after 6 months and there was no further improvement after this period (which may have been due to the fact that it corresponded to the summer period: chloasma is worsened by exposure to ultraviolet light).
It is known that oxygen-derived free radicals (reactive oxygen species) cause tissue damage in acute and chronic pancreatitis. Two US-based clinicians hypothesised that GSE being a powerful antioxidant, might be useful in managing the symptoms of chronic pancreatitis.2 The extract was given to three patients with well-established disease whose severe symptoms were unresponsive to standard treatments. The addition of GSE to their treatment regime led to a reduction in the frequency and intensity of abdominal pain, as well as resolution of vomiting in one patient. Abdominal pain is the most common symptom of chronic pancreatitis and a striking feature of the treatment with GSE was the substantial reduction in the severity of pain experienced by the patients (based on a numerical rating scale, pain was on average halved).
At 200 mg/day, the prescribed dose of GSE extract in these case studies was higher than what is normally used. This was increased to 300 mg/day during worsening of symptoms. Such doses can cause constipation as a side effect in sensitive people (similar to the way that the tannins in tea can cause constipation). While this study only contains three case histories, it is a promising lead for the herbal therapy of a difficult and severe disorder. If pancreatitis is associated with excessive alcohol consumption, then milk thistle extract might also be beneficial.
Results from two clinical trials published within the last three years suggest that GSE also has a useful role to play in the management of other modern chronic disorders. Non-alcoholic fatty liver disease (NAFLD) affects 10 to 24 per cent of the general population and may progress to end-stage liver disease. It usually occurs in people who have too much fat around their waists and as a result have become insulin resistant. Evidence-based treatment options are limited. A small study evaluated the effects of a GSE product in comparison to ascorbic acid over 3 months in a double blind setting.3 Fifteen patients were enrolled in each group. Serum levels of ALT decreased significantly in patients receiving GSE, indicating less liver inflammation. Additionally GSE significantly improved the grade of liver steatosis (fatty streaks), as assessed by ultrasound. The GSE used in the trial was formulated in 100 mg capsules, but the daily dosage was not provided (presumably 100 to 200 mg/day). No significant benefits were observed for the 1,000 mg/day ascorbic acid treatment.
Thirty-two type 2 diabetes patients, prescribed diet or oral glucose-lowering drugs, received GSE (600 mg/day) or placebo for 4 weeks in a double blind, randomised, crossover trial.4 Following GSE (but not placebo), significant changes from baseline were noted for fructosamine (a measure of blood sugar control), whole blood glutathione (a measure of antioxidant status) and highly sensitive C-reactive protein (hs-CRP, a measure of inflammation). There were no statistically significant changes for insulin resistance, and no changes for anything measured in the placebo group.
To your better health,
Nutrition & Healing
Volume 6, Issue 9 – September 2012
Full references and citations for this article are available in the downloadable PDF version of the monthly Nutrition and Healing issue in which this article appears.