Functional Beverages – Is it possible to drink yourself fit ?
Drinks that claim to have health benefits are the largest and fastest growing segment of the functional foods sector. The market is growing at over 20% a year and health drinks are now commonly available in every local supermarket, petrol station and shop. Health claims range from simply boosting energy and immunity to improving cardio-vascular health, aiding weight loss and even lowering cancer risk…. but can they be believed?
This summer I set myself the project of reading the recently published ‘Handbook of Functional Beverages and Human Health’ edited by Fereidoon Shahid and Cesarettin Alasalvar (CRC PRESS 2016). This 866page door stop of a book aims to summarise all the current research on this thriving sector, which by 2017 is expected to be worth over $1347 billion globally. The book is divided into seven main sections, covering fruit juices, herb and vegetable juices, caffeinated drinks, dairy and dairy replacement, fermented drinks, alcoholic drinks and fortified drinks (including pro and pre-biotic, omega3, peptide enriched etc). Each section is written by the foremost researchers in that field – the list of contributors alone goes on for nine pages.
What did I learn ?
Although they are not likely to be the first ones that come to mind, the most popular functional beverages are coffee and tea.
TEA – Other than water tea is drunk more than any other drink worldwide. The chemistry of tea is very complicated, over 4000 different phyto-chemicals have been identified, many of which have been shown to be bioactive. Tea polyphenols account for 25-25% of total dry weight with higher concentrations present in unfermented green tea than the fermented black tea. Research is strong – Drinking tea has been universally found to be calming and to lower stress. Green, Oolong and Black tea have been shown to reduce hypertension and lower blood cholesterol in humans, lo
wering cardiovascular risk. All types of tea are shown to be antioxidant and anti-inflammatory and have anti-bacterial and anti-viral properties. Drinking tea has been shown to protect the ageing brain and reduce incidence of neurodegenerative diseases.
COFFEE – There are 70 different species of coffee and each has a slightly different phytonutrient profile. The two most common types are Robusta,which is a lowland coffee and Arabica, which is grown at altitude close to the equator. 60% of coffee drunk worldwide is arabica and arabica coffee definitely has the superior taste profile – though Robusta contains more antioxidants and caffeine. Coffee like tea contains lots of
tochemicals and these have been well studied. The major bioactive phenolic compounds in coffee are the chlorogenic acids (CGAs) and the latest research suggests that these may act by modulating gene expression as well as having direct health effects. Coffee consumption has been associated with reduced risk of chronic and degenerative diseases such as cancer, diabetes, liver disease, Parkinsons, inflammatory diseases and Cardio-vascular disease. Bioactivity of coffee is highly dependent on type, growing conditions, roasting, storing, blending and brewing. Most of the research to date has concentrated on caffeine content. I believe that this is missing a trick.
After tea and coffee the most often consumed drinks are fruit based. Section two of the book contains articles about 38 different fruit juices covering everything from apple to hawthorn and including several Ive never heard of. Orange is the most commonly drunk fruit juice followed by apple juice. For both of these there is a very wide variety of different qualities and preparations available and it is suggested that more information is needed for consumers on the relative health benefits. I think the conclusion is that cloudy or bitty is best.
All the fruit beverage research pieces outline the benefits of eating / drinking fruit. All the different fruits have good phytonutrient content and mineral profiles. I have outlined the ones I found the most interesting below:-
BLACKCURRANT – I may be bias here because Chichester University has been involved in a lot of blackcurrant research (see ‘Blackcurrants -possible new ergogenic aid’) and I love to grow blackcurrants but I do think the research on their benefits is particularly strong. I also like how the authors (Bolling, Martin, Pei, Xie and DiMarco) question the analysis of the composition of blackcurrant juice used in much of the research and also the bioavailability of the phytonutrients within a mixed diet. They also comment on the huge variation of polyphenol content depending on differing cultivars, growing conditions and processing methods which I think is important. They conclude that there is good evidence that blackcurrant juice can reduce biomarkers of inflammation and oxidative stress, as well as being a great source of vitamin C and potassium. The recent research from Chichester has shown that blackcurrant extract can also improve cycling time-trial performance and increases fat oxidation during moderate intensity cycling. I believe one of the biggest assets of blackcurrants is that they are not overly commercialised and have not been selectively bred for appearance or yield.
COCONUT JUICE – I have been a little scathing of the trend of drinking coconut water after exercise but having read this perhaps I should reconsider. I knew that coconut juice or water was rich in electrolytes and high in vitamins (particularly Bvits) and minerals but I didn’t know that it also contains a rich cocktail of enzymes, free amino acids and phyto-hormones, all of which are potentially bioactive. Coconut water has been shown to reduce blood glucose, modulating insulin and boosting the enzymes involved in carbohydrate metabolism and the phytohormones support cell division, growth and repair. Research shows foods high in phyto-oestrogens are beneficial in postmenopausal women and also for Alzheimers disease. There is also good evidence that the bioactive enzymes aid digestion and lower blood pressure particularly in stress.
NONI JUICE – I had never even heard of a noni plant. Its a tropical plant originally from North Australia and New Guinea. The fruit is reported have an unpleasant flavour and smell but has been very important in traditional medicine and has become very popular as a wellness drink. Fermented and unfermented drinks have been shown to increase energy, improve sleep, lower infections, lower pain, reduce headaches, and reduce allergies. In sport, drinking a commercially available noni juice for two weeks caused a 20% increase in time to exhaustion on a treadmill as well as showing reduced markers of oxidative stress.
PEAR JUICE – All fruit juices have a rich content of Phytonutrients, minerals and vitamins and pears are no different. Korean pears however are the only juice that has specifically been linked to reduction in alcohol toxicity and hangover reduction. More than one large and well conducted study have shown that drinking pear juice can reduce hangover severity and improve mental capacity and concentration. Pear juice has also been shown to improve iron bioavailability and is a FODMAP food, stimulating biofidobacteria growth in the colon.
Section three, on herbs and vegetables is disappointing. I believe the research on fruit and vegetables conclusively shows that vegetables are possibly even more important in the diet than fruit but the book only covers carrot, tomato, Chinese herb and mixed veg. This is possibly due to lack of good research. Isn’t tomato a fruit anyway?
The best of the rest…..
DAIRY BEVERAGES – Although the vast bulk of this book is dedicated to fruit juices, the number of bioactive and essential constituents in milk is far far greater than any single fruit or vegetable juice. I have written about milk before and am a fan (see Cows milk – healthy or bad for you? and Milk – The new sports drink ) and there is still more here that promotes milk. Unfortunately the best possible evidence is for unpasteurised, homogenised milk and this is often hard to come by and there is also a lot of research on the health benefits of Colostrum. Other bioactive components include branch chain amino acids, glycomacropeptide (GMP), lactoferrin, protein hydrolysates and phytosterols.
FERMENTED DRINKS (Kefir, Koumiss and Ayran) – Drinking fermented milk based drinks has evolved independently in many different areas of the world and are generally thought to be health promoting. Kefir originates in the caucasian mountains and Mongolia and is made from cow or goat milk with kefir grains. It is lightly self-carbonated and contains more than 30 different beneficial micro-organisms and is a good source of a number of bioactive peptides, essential amino acids and conjugated linoleic acid (CLA). Fermentation also increases the bioavailability of minerals such as calcium, iron, phosphorus, magnesium, potassium, sodium, copper, zinc, molybdenum and manganese and also of B vitamins. Koumiss is made from mares milk and is mildly alcoholic. Mares milk is the closest animal milk to human milk. Koumiss contains a wide variety of beneficial micro-organisms and is a good source of vitamins but has surprising low mineral content. Ayran is made from ⅓ yoghurt and ⅔ water with salt and herbs. Its very popular in Turkey and is generally made with ewes milk. All fermented drinks have been found to have credible health benefits and demonstrate antimicrobial, antihypertensive, antioxidant, anticytotoxic, immunomodulatory, opioid and mineral carrying properties. Making and drinking fermented mild drinks has been linked with better health outcomes and lower all disease risk. Kefir, Koumiss and Ayran have been shown to lower stress and anxiety and to improve insomnia. More research is needed but I feel there is huge potential in this type of beverage.
Usually when I review a book, I recommend that you read it. I would not recommend this book, not only is it very heavy but it is expensive and a little dry. This doesn’t mean its not interesting or well written – there has been a lot of detailed and well designed research, particularly into fruit juices and there are some very interesting suggestions for future research.
Although its an easy way to increase your fruit and vegetable consumption, there is nothing in this book that convinced me that its better to drink things than eat them and I will continue to recommend eating whole fruit rather than buying juices. The large number of possible fruit juices and the wide variety of different constituents did however remind me of the value of eating lots of different fruits and vegetables and not just sticking to the familiar few.
I was also reminded of the health claims of fermented food and drinks and will definitely be trying some of these.
Dont be blinded by marketing….. Research shows that 70% of purchasing decisions are made at the point of sale and the main factor influencing this decision is the packaging and not the food/drink itself. As the health drink market increases, there has been considerable research on how foods can best be made into palatable drinks and on the health claims that can be made. Less research has been done on the effects of varietal, growing area, harvesting, processing and storage