Robert Verkerk explores why turmeric and its medicinal actions has won so many advocates the world over.
Ancient, tried and tested, multi-faceted, proven, the closest thing to a magic bullet, state-of-the-art…? These are just some of the ways of describing turmeric’s remarkable properties. A paper published in 2016 in the peer-reviewed journal Current Topics in Medicinal Chemistry linked the following biological and pharmacological activities to curcumin, the predominant active principle in turmeric: “a natural antioxidant… anti-inflammatory, anti-microbial, anti-cancer, anti-Alzheimer…anti-tubercular, cardio-protective, anti-diabetic, hepato-protective, neuro-protective, nephron-protective, anti-rheumatic and anti-viral” (from Synthetic and Medicinal Prospective of Structurally Modified Curcumins). No licensed pharmaceutical drug can get close to having such a broad range of effects on the body. There are now over 7000 published research studies that have shed light on the antioxidant, hypoglycaemic, anti-inflammatory and anti-cancer activities of turmeric’s most studied active principle, curcumin (from The beneficial role of curcumin on inflammation, diabetes and neurodegenerative disease: A recent update).
The rhizome (root) of this perennial herb, known scientifically as Curcuma longa and belonging to the ginger family, is cultivated extensively in south and southeastern tropical Asia. It has become one of the hottest properties in natural medicine. So much so that it has the pharmaceutical interests salivating over how it can tweak some of turmeric’s active principles to create synthetic analogues that can then be patented (from Synthetic and Medicinal Prospective of Structurally Modified Curcumins).
Multi-target functionality
Extensive research, especially during the last two decades, has revealed that the multiple effects on the body are linked to turmeric’s effects not on just one target within the body, but multiple targets (see Perspectives on New Synthetic Curcumin Analogs and their Potential Anticancer Properties). The potent anti-inflammatory effects of the most thoroughly studied active principles, known collectively as curcuminoids, are thought to be associated with their ability to upregulate one of the main anti-inflammatory pathways known as PPAR-gamma, which in scientific speak stands for ‘peroxisome proliferator-activated receptor-gamma’(see Mechanism of the Anti-inflammatory Effect of Curcumin: PPAR-gamma Activation). Besides this, curcuminoids are thought to suppress the proliferation and metastasis of human cancers through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases and other enzymes (see Perspectives on New Synthetic Curcumin Analogs and their Potential Anticancer Properties). Clinical studies based on turmeric have shown benefits in the treatment of lupus nephritis, cancer, diabetes, irritable bowel syndrome, acne and fibrosis (see Multitargeting by turmeric, the golden spice: From kitchen to clinic).
Owing to the much acclaimed anti-inflammatory and antioxidant actions, there is also increasing interest in turmeric’s role in managing inflammatory conditions, such as osteoarthritis, and pain around joints osteoarthritis and joint pain a feature that has been noted by an increasing number of sports scientists (see Mitigation of Systemic Oxidative Stress by Curcuminoids in Osteoarthritis: Results of a Randomized Controlled Trial). Nrf2, Nuclear factor (erythroid-derived 2)-like 2, is involved in cellular responses to oxidative damage triggered by injury and inflammation and plays a key role in managing various pathways and protecting our organs. Numerous studies have shown this Nrf2-conferred, multi-organ protection phenomenon protects many cell types and organ systems from a broad spectrum of toxic insults and disease pathogenesis. Turmeric can have a direct, up-regulatory effect on the body’s production of this specific nuclear factor. When Nrf2 is activated, NF-kB pathways are mediated and downregulated. This demonstrates how bioactive compounds, including turmeric, can have multiple ‘knock-on’ beneficial, preventive and therapeutic effects.
Another burgeoning area of research is the role of active principles within turmeric on neurodegenerative conditions such as Alzheimer’s disease, which currently do not respond well to any existing drugs. Curcuminoids hold real promise, not only because of their proven anti-inflammatory and antioxidant effects, but also because they directly limit the production of β-amyloid plaques known to be the primary cause of Alzheimer’s disease (see Examining the potential clinical value of curcumin in the prevention and diagnosis of Alzheimer’s disease).
It is no wonder that turmeric is sometimes referred to as the “golden spice” or the “goddess of spices”. It has a documented track record linked to its incredible properties, when ingested or rubbed on the skin in oil form, that goes back over 4000 years in the ancient vedic texts. With the increased recognition that most ‘modern diseases’ are multi-factorial and linked to excessive, or poorly controlled inflammation, oxidative stress and improperly modulated immune systems, research on turmeric and its active compounds and analogues is now at an all-time high.
Millions have experienced the benefits of turmeric, benefiting from its multi-target functionality to help keep them bouncing with health and vitality for longer. Most drugs (most of which are either entirely new-to-nature or are synthetic analogues of isolated plant compounds) can only dream about having this broad range of effects on the body, with no side effects to speak of, unless very, very high dosages are consumed.
This brings us onto the next topic. To get the most out of turmeric, you need to consume the whole root; or at least an extract made from the whole root. Many preparations currently available on the market are standardized extracts containing un-naturally high levels of curcumin. The fat portions of plant material are notoriously difficult to draw out of a plant and, historically, harsh chemicals have been one of the only ways by which to extract them. These have included chemicals such as hexane and various hydrocarbons. The problem with such solvents arises when they are used over a prolonged period and build up in the body. And, perhaps unsurprisingly so, there have also been links between such solvents and chronic illnesses. So, always keep an eye out for whole root preparations and extraction methods that use natural alternatives to harsh chemicals.
No one trick pony
My own experience of turmeric started many years ago. I was drawn to the yellowy orange spice in Indian and South East Asian cooking because it had the capacity to be such a key player in both the kitchen and the clinic. My personal interest in using the spice therapeutically increased again as I became progressively more active with age, partaking in endurance sports, especially cycling. The most researched active principle in turmeric is curcumin, which typically makes up around 2 to 5% of the turmeric rhizome (see High performance curcumin subcritical water extraction from turmeric (Curcuma longa L.)).This single compound, a natural phenolic known chemically as diferuloylmethane, is responsible for the yellow colour of turmeric. Just this one compound exerts multiple effects on the body, working particularly as an anti-inflammatory, antioxidant and as a cancer prevention agent. But there’s more. Curcumin has been shown to improve insulin sensitivity by upregulating downstream signaling systems (such as AMPK) which helps reduce the risk of type 2 diabetes and heart disease to boot. If that wasn’t enough, curcumin also helps to modulate the immune system.
Even more exciting is that the broad range of effects are not isolated to just one active principle. Turmeric contains a complex of compounds called curcuminoids, the three most well studied being curcumin, demethoxycurcumin and bis-demethoxycurcumin (see Production of Curcuminoids in different in vitro organs of Curcuma longa). In addition to this, turmeric contains essential oils that have been shown independently of the curcuminoids, to yield anti-mutagenic and anti-carcinogenic effects (see Chemopreventive activity of turmeric essential oil and possible mechanisms of action).
Research on turmeric is set to continue for years, as more and more of its properties are revealed. One particularly interesting strand of research relates to finding new active principles, other than curcumin. This work includes research using curcumin-free extracts containing other components in turmeric such as turmerin, turmerone, elemene, furanodiene, curdione, bisacurone, cyclocurcumin, calebin A and germacrone are exhibited; these have still shown profound anti-inflammatory activity (see Curcumin-free turmeric exhibits anti-inflammatory and anticancer activities: Identification of novel components of turmeric).
With such a heady range of beneficial effects on the human body, you may be asking yourself why hasn’t everyone switched to using turmeric and its diverse range of active principles, why haven’t most of the diseases which it targets disappeared, and why hasn’t the pharmaceutical industry as we know it collapsed through lack of demand for its new-to-nature offerings? Despite copious evidence of turmeric’s diverse effects in laboratory systems or animals, human clinical trials haven’t always shown consistent effects, despite the balance of evidence being positive, rather than neutral or negative. Much of this appears to be linked to the type of formulations that have been studied by researchers, these generally being highly purified curcumin, which has been found to have poor water solubility, poor bioavailability and be rapidly metabolized in the body (see Heterocyclic Curcumin Derivatives of Pharmacological Interest: Recent Progress).
An important property of turmeric essential oil can be to enhance the bioavailability of the main active principles, the curcuminoids. This means that bioavailable formulations that contain the full complex of curcuminoids, other active principles along with turmeric essential oils, have a combination of effects on the body, that can potentially get you about tantalisingly close to the ‘holy grail’ of herbal medicine. It’s theoretically possible that the effects of full-spectrum turmeric can be enhanced further when consumed along with healthy fats (e.g. ghee, olive oil, coconut oil, omega-3 fatty acids) in the diet. Unfortunately, very few studies have been undertaken with these kinds of products used under optimal conditions. But decades of experience from informed and experienced clinicians, as well as patients and, increasingly athletes, strongly supports this approach. It is entirely plausible therefore that bioavailable, full-spectrum turmeric extracts be regarded as something of a panacea in natural healthcare and self-care.
Natural running partners: Physical activity and turmeric
More and more of us are turning our backs on sedentary lifestyles and are incorporating regular physical activity and other healthy lifestyle habits into our already busy lives (see Lifestyle Changes and Mortality in Men). This is a natural response to increased awareness that sedentary lifestyles, along with poor quality, insufficiently diverse diets based around highly processed foods, are among the biggest causes of ill-health and premature death in society.
But is it a double-edge sword? Intense physical activity or extended endurance exercise has been shown to put a real strain on the musculo-skeletal system, joints, cardiovascular system and immune system, contributing in the process to prolonged inflammation (see Effects of Mountain Ultra-Marathon Running on ROS Production and Oxidative Damage by Micro-Invasive Analytic Techniques).
This exercise-induced stress to which athletes expose themselves makes this group particularly vulnerable to joint, tendon or muscular injuries — and may compromise their immune systems leaving them open to increased infection risk, especially of the upper respiratory tract (see Limits of Human Endurance). This can especially be the case following very intense bouts of training on the lead up to major athletic events — just when the infection is least welcome!
Regular, intense training is well known to yield a mixture of positive and negative effects, and it must be comforting for some that rigorous follow-up of male elite athletes tends to suggest an overall balance towards positive effects on healthy lifespan (see Health status of former elite athletes. The Finnish experience).
However, we can’t escape the fact that long-term engagement with intense, vigorous exercise contributes to persistent, elevated levels of oxidative stress in the body. This is where the production of reactive oxygen species (free radicals) in the body can’t keep pace with antioxidants which have the ability to quench them. Some antioxidants are produced internally, like glutathione, while others are consumed as part of the diet, such as polyphenols that include the colourful pigments in fruits, vegetables, herbals and spices. Curcuminoid pigments in turmeric rhizomes range from yellow to orange in colour. If sufficient dietary antioxidants are not supplied, and an athlete doesn’t give him- or her-self sufficient time to recover between bouts of exercise, the athlete’s performance will suffer, rather than improve, despite continued training. If that were not enough, the sheer level of oxidative stress and prolonged inflammation to which an individual can be exposed through years of intense training, especially among professional athletes, may also accelerate ageing if dietary antioxidant levels are not maintained.
For these reasons, and because of its multi-target function, turmeric extracts are proving amazingly popular with athletes, amateur and professional alike. To deliver the best results, there can be no substitute for using bioavailable forms of supplemental full-spectrum turmeric, which may benefit from further enhancement by consumption alongside foods with significant levels of healthy fats, such as ghee (clarified butter), olive oil or coconut oil (see Utilizing food matrix effects to enhance nutraceutical bioavailability: increase of curcumin bioaccessibility using excipient emulsions). Additionally, because of the fat solubility of some of the key principles in turmeric, turmeric oil can also be applied to the skin, especially to aid wound-healing, to protect the skin from damage and help treat a variety of dermatological diseases (see Effects of Turmeric (Curcuma longa) on Skin Health: A Systematic Review of the Clinical Evidence). It is also thought that there may be some cutaneous absorption through the skin in some types of oil formulation with the aim of yielding anti-inflammatory effects close to the areas of application, such as around joints and tendons. More and more athletes therefore see a good quality turmeric oil as the massage oil of choice.
Turmeric, consumed in foods, and used in medicines taken both orally and topically, has an almost unique track record as a food, herbal and medicinal ingredient over the 4 millennia or so of recorded human history. It is only very recently that we’re starting to understand much more clearly the sophistication of turmeric’s complex activity, so underpinning why the right turmeric formulations, used both orally and topically, have won so many advocates the world over.
In the process, turmeric extracts are now among the hottest ingredients in many leading athletes’ natural health toolboxes. Given the quality issues over some food (dietary) supplements, it is also reassuring that there are no risks of encountering problems with banned substances given turmeric’s status both as a culinary spice and a potent, multi-functioning herbal medicine.
