In a category under pressure from rising prices and underproduction, fruits and the premium-priced cousins the 'superfruits' need new and innovative products to draw in the consumer. As 2009 approaches, what superfruits will provide exciting and healthy options for the naturalproducts market? Mark J Tallon, PhD, investigates
Why are some fruits classed as 'super'? It has been suggested that some fruits have an innate nutrient profile that offer nutritional benefits above and beyond most other fruits. It all began with the characteristically American cranberry and the Himalayan-born pomegranate. Cranberries' clinical data was of such quality and depth that in 2004, France granted a specific health claim for American cranberries (Vaccinium macrocarpon). The claim, "helps to reduce the adhesion of certain E. coli bacteria on the urinary tract wall," was given for the delivery of 36mg proanthocyanidins per serving. The French Food Safety Authority has recently extended its approval of the health claim in line with the potential acceptance of a submission to the European Food Safety Authority.
Similarly, pomegranate has been a huge headliner in 2008, as news reports revealed adulteration of some products with sugars rather than pomegranate solids. However, despite the negative press, the well-known cardiovascular and prostate/breast-health potential of pomegranate has taken a step forward with data indicating joint and weight-loss potential.1,2
Datamonitor predicts double-digit growth from 2006 to the end of 2008, though if one takes a closer look at the scientific evidence, the popularity of other superfruits has grown faster than the available scientific evidence. Much of the research backs up the antioxidant capacity of such products, which is by no means unhealthy, though the market could benefit even more with solid research showing definitive evidence that these exotic fruits positively influence health and wellbeing beyond antioxidant superpowers. To date, much of the past research is limited to in vitro and in vivo studies, though industry experts are just beginning to see emerging science and small clinical trials that supports the rising popularity. Here is an overview of the emerging next generation of superfruits.
Gac (Momordica cochinchinensis): Gac is a Southeast Asian fruit found throughout southern China to northeastern Australia. It has a traditional history of use for its medicinal and nutritional properties such as aiding in the relief of dry eyes, as well as promoting healthy vision. However, peer-reviewed publications show gac to be high in the carotenoids lycopene (70 times the amount found in tomatoes) and beta-carotene (10 times the amount in carrots).3 Beyond its excellent nutrient profile, gac has some interesting clinical trial data that may support product health claims.
A trial conducted at the University of California assessed a beta-carotene-rich rice preparation as a source of provitamin A for children in rural Vietnam.4 In a 30-day trial 185 children were assigned to one of three groups: rice and gac containing 3.5mg beta-carotene (RG), rice with synthetic beta-carotene (RSB), or rice without fortification (RW).
The results suggest that beta-carotene delivered as gac rather than powder has much greater bio-availability. The mean increase in plasma beta-carotene concentrations with RG and RSB was significantly greater than that in the control group. After supplementation, the mean plasma retinol concentration in the RG group was also significantly higher than that in the control or powder groups. Of note is that there was a mean increase in haemoglobin concentrations in the RG group, which was marginally higher than that in the control group.
This study demonstrates that beta-carotene from RG is a good source of provitamin A carotenoids, which are more bio-available than when delivered as a powder. Furthermore, those suffering from anaemia may find gac to be a beneficial nutrient in supporting oxygen-carrying capacity through enhanced haemoglobin levels.
In a trial to further examine the antioxidant potential of gac, researchers from the Chinese University Hong Kong examined the ability of gac to prevent oxidative liver damage.5 Although only a cell study, it does show that gac reversed the depletion of some of the body's most important antioxidants (glutathione) and markers of cell damage (lipid peroxidation), while increasing antioxidant enzyme levels (glutathione-S-transferase and superoxide dismutase). These results suggest that gac possesses significant antioxidant potential, accounting for some of the potential health benefits associated with its use.
Indian gooseberry/Amla (Phyllanthus emblica): The Indian gooseberry is a popular fruit used extensively in Ayurvedic herbal preparations, and is high in tannins. Unlike many superfruits, amla has a significant number of human trials indicating areas of potential effectiveness, as well as some more novel cell-culture trials indicating new applications in human health.
In one of the early trials on amla, the University of Delhi assessed the effect of dietary supplementation on cholesterol levels in healthy and hypercholesterolaemic men.7 The supplementation period was conducted over 28 days, which led to a significant decrease in cholesterol in both normal and hypercholesterolaemic subjects. Two weeks after withdrawing the supplement, total serum cholesterol of the hypercholesterolaemic subjects rose significantly to almost initial levels.
A 2007 study investigated the effects of an amla preparation on memory, total serum cholesterol levels and brain cholinesterase activity in mice.8 Amla was administered orally in three doses (50, 100 and 200mg/kg) for 15 days to different groups of young and aged mice. The study tested for memory following chemically induced ageing and Alzheimer's. Additionally, total serum cholesterol levels and brain cholinesterase activity were estimated. Amla produced a dose-dependent improvement in memory scores of young and aged mice, and reversed the effects of chemically induced amnesia. Interestingly, brain cholinesterase activity and total cholesterol levels were reduced by orally administered amla.
Amla may prove to be a useful remedy for the management of Alzheimer's disease on account of its multifarious beneficial effects such as memory-improving property, cholesterol-lowering property and anticholinesterase activity.
Amla's antioxidant vitamin and polyphenol profiles may provide protection for human dermal fibroblasts (skin cells that give the skin its strength and resilience), and therefore it is thought to be useful for natural skincare. In a study from Japan, researchers investigated the effects of amla extract on human skin, and its ability to enhance production of procollagen and matrix metalloproteinases (MMPs) to combat broken-down, damaged or worn-out structural proteins (ie, collagen).9
Amla stimulated growth of fibroblasts in a concentration-dependent manner, and also induced production of procollagen (precursor of collagen, the protein that adds strength and support to many body tissues) in a concentration-dependent manner. Conversely, amla decreased MMP production from fibroblasts. These early results demonstrate the potential of amla to enter the cosmeceutical markets, as it may provide an effective method of enhancing collagen metabolism and better-looking skin.
Lychee (Litchi chinensis): The lychee is a tropical fruit native to southern China and southeast Asia, and provides a good source of vitamin C and potassium. It is a well-known fruit in the West, currently finding applications as a dried product across categories within and external to the nutrition market.
In a 2007 study a lychee extract was evaluated for its ability to protect the liver.10 The trial compared a dried lychee extract to a saline control following a chemical assault known to cause liver toxicity. Baseline measures of liver function were recorded pre- and nine days post-chemical assault. Lychee significantly protected the liver compared to a saline control. These results were substantiated by both histological examination and biochemical assessment of liver damage.
The results of this trial highlight that an aqueous extract of fruit pulp of lychee can provide a significant hepatoprotective effect. This trial gave a glimpse of proof of concept, but further work on humans may offer up solutions in the current detox beauty markets.
Acerola (Malpighia emarginata): Also know as Barbados cherry, acerola produces a bright red fruit well known for its vitamin C content that is 20 times that found in most oranges. Acerola is a popular fruit in Japan, especially within the beverages market, which has made a greater move into functional-nutrition categories of late. Its potential in cosmetic markets, due to its high vitamin C concentration, is of increasing interest. Recent studies indicate it also may help in other categories of health and well being, such as blood-sugar control.
In a Japanese study, an acerola extract was used in an animal trial to investigate its potential as an anti-hyperglycaemic agent.6 In a test administrating glucose and maltose, plasma glucose was measured as an indication of absorption with or without acerola.
Results revealed that acerola significantly suppressed plasma glucose following both glucose and maltose supplementation. This suggests it has a preventive effect on hyperglycaemia. The mechanism behind these effects may include suppression of intestinal-glucose transport and inhibition of alpha-glucosidase, which is involved in the breakdown of carbohydrates.
The real superfruits
Although consumers look for superfruits with a tropical origin, many commonly known fruits, such as bananas, could also be defined as superfruits based simply on their potential to benefit blood pressure because of high potassium levels. However, consumers prefer the novelty of the tropical ingredients and a new taste experience, as much as a health claim. The near-term options for superfruits will most likely follow this trend by focusing on antioxidant capacity and exotic country of origin, with rare fruits such as yuzu (Citrus ichangensis) and yumberry (Myrica rubra), and those listed above making headway. This type of consumer demand can only be met for a limited period as the market runs out new fruits from Asia and Africa. As supply declines, the market will see a greater move to functional fruits that offer health benefits such as high fibre (potential appetite claims) and health effects for specific conditions.
Mark J Tallon, PhD, is chief science officer of NutriSciences, a London-based consultancy firm specialising in health-claim substantiation, product development and technical writing.
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1. Shukla M, et al. Consumption of hydrolyzable tannins-rich pomegranate extract suppresses inflammation and joint damage in rheumatoid arthritis. Nutrition 2008; 24(7-8):733-43.
2. Lei F, et al. Evidence of anti-obesity effects of the pomegranate leaf extract in high-fat diet induced obese mice. Int J Obes (Lond) 2007;31(6):1023-9.
3. Ishida BK, et al. Fatty acids and carotenoid composition in gac (Momordica cochinchinensis spreng) fruit. J Agri Food Chem 2004;52:274—9.
4. Vuong le T, et al. Plasma beta-carotene and retinol concentrations of children increase after a 30-day supplementation with the fruit Momordica cochinchinensis (gac). Am J Clin Nutr 2002;75(5):872-9.
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9. Fuji T, et al. Amla (Emblica officinalis Gaertn.) extract promotes procollagen production and inhibits matrix metalloproteinase-1 in human skin fibroblasts. J Ethnopharmacol 2008 Jun 6. [Epub ahead of print].
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