(BEING CONTINUED FROM 30/05/17)
A global score was then calculated to summarise the strength of evidence available for each functional ingredient (Table (Table3).3). To take into account the quality and quantity of RCTs, the global score was calculated by adding a factor to the mean quality score of the RCTs (that is, 0.33 when two positive high-quality RCTs were available, 0.66 when three positive high-quality RCTs were available, and 1.00 when four positive high-quality RCTs were available). Likewise, when two, three, or four negative high-quality RCTs were available, 0.33, 0.66, or 1, respectively, was subtracted from the mean quality score of the RCTs. Adding a factor gives more weight to the high-quality trials and helps to prevent the ‘dilution’ of the outcomes of high-quality trials when numerous low-quality trials exist. It also distinguishes the functional ingredients supported only by one, two, three, or four high-quality trials, which would otherwise end up with the same global score.
Consequently, the scores range from -2 to +2:
▪ A score below -0.5 corresponds to at least some evidence of inefficacy.
▪ A score between -0.5 and +0.5 indicates a lack of evidence of efficacy because it is obtained in case of conflicting evidence or when a majority of poor-quality trials are available.
▪ A score greater than 0.5 but less than or equal to 1 corresponds to limited evidence of efficacy because it is obtained when a majority of medium-quality trials exist in the presence of a maximum of one positive high-quality trial or when a single positive high-quality trial is available.
▪ A score between 1.01 and 1.33 indicates moderate evidence of efficacy because it requires two positive high-quality trials in the absence of major conflicting evidence.
▪ A score between 1.34 and 1.66 indicates good evidence of efficacy because it requires three positive high-quality trials in the absence of major conflicting evidence.
▪ A score between 1.67 and 2.00 indicates very good evidence of efficacy because it requires four positive high-quality trials in the absence of major conflicting evidence.
Out of the 2,026 identified studies, 52 RCTs that investigated the effects of functional ingredients in OA and that had their results reported in peer-reviewed full papers were identified. Historically, functional ingredients can be derived from primary food sources, from secondary food sources, from traditional medicinal products from all around the world, or from materials with no history of human exposure (for example, stanols from paper industry by-products for their cholesterol-lowering effects) . The situation regarding OA is no different. Some ingredients included in this review are from primary food sources (for example, n-3 polyunsaturated fatty acids [n-3 PUFAs]), from secondary food sources (for example, ginger), from traditional medicinal products (for example, cat’s claw), or from material with no history of human exposure as such (for example, ‘hyperimmune’ milk). The investigated nutritional interventions focused on lipids (avocado and soybean unsaponifiables [ASUs], n-3 PUFAs, lipid extracts from New Zealand green-lipped mussel, and cetyl myristoleate), on vitamins and minerals (vitamins C, E, B3, and B12, boron, a cocktail of vitamins and selenium, and a cocktail of minerals), on plant extracts (bromelain, Rosa canina, Harpagophytum procumbens, Uncaria tomentosa, and Uncaria guianensis, Salix sp., ginger, turmerics, tipi tea, soy proteins, and Boswellia serrata), on a cocktail of plant extracts (SKI306X, Gitadyl, Duhua Jushing Wan, and Articulin-F), and on a few other types of ingredients (methylsulfonlymethane, hyperimmune milk, and collagen hydrolysate).
(TO BE CONTINUED)
Laurent G Ameye and Winnie SS Chee