Last month “Nutrition 2018” was held in Boston. It was the inaugural flagship meeting of the American Society for Nutrition. Evidence from several studies was presented showing that a primarily plant-based diet is linked to numerous health benefits. Obviously, the quality of the food was important as well. Here is a summary of 5 papers that were presented:
- A 13 year study of 6000 people in the Netherlands found that a higher proportion of dietary plant protein to animal protein was linked to lower risks of developing heart disease.
- A study of 4500 Brazilians showed that those eating more plant-based protein were 60% less likely to have coronary artery plaque than those consuming more animal-based protein.
- South Asians living in the US that followed a vegetarian diet had a lower number of risk factors for heart disease and diabetes (lower body mass index, smaller waist circumference, less abdominal fat, lower cholesterol levels, lower blood sugar levels) than those that ate meat.
- A 4-year American study of over 125,000 adults showed that a whole food plant-based diet (whole grains, fruits, vegetables, nuts, etc.) led to less weight gain than a processed plant-based diet (sweets, refined grains, fries, etc.).
- A study on 30,000 American adults demonstrated that improving the quality of the plant-based component of diet decreased mortality by 30% whereas improving the quality of the animal-based components had little effect. Among people with chronic health problems these beneficial effects were even more pronounced.
These recent research findings add to the mounting body of evidence supporting the health benefits of a whole food plant-based diet.
Zhangling Chen et al., from Erasmus Medical Centre in the Netherlands, presented new research on diet at this year’s European Congress on Obesity. Their findings were based on a long-term study observing around 10,000 middle-aged and elderly adults from the Rotterdam Study. The results showed that people eating a higher proportion of plant-based foods have lower waist circumferences and BMIs, mainly due to lower body fat mass.
As we already know, obesity is associated with elevated levels of inflammation and greater risks of getting “diseases of affluence” such as diabetes, heart disease, stroke, cancer and osteoarthritis.
According to the authors: “a more plant-based and less animal-based diet beyond strict adherence to vegan or vegetarian diets may be beneficial for preventing overweight/obesity in middle-aged and elderly populations. In other words, eating to protect against obesity does not require a radical change in diet or a total elimination of meat or animal products. Instead, it can be achieved in various ways, such as moderate reduction of red meat consumption or eating a few more vegetables. This supports current recommendations to shift to diets rich in plant foods, with low consumption of animal foods.” This conclusion is reassuring and encouraging for all those that would like to make some dietary changes but are intimidated by the effort and motivation required to completely overhaul their diets. We have to start our journey somewhere…and just a few steps in the right direction can start to make a difference!
It’s well-known that obesity can cause or exacerbate osteoarthritis (OA) through excessive mechanical loading. But another mechanism through which obesity can affect joint health is via inflammation and we now know that our gut microbes play a crucial role.
Recent research by Schott et al. has looked into the link between obesity, gut microbes and OA. They found a difference between the types of gut bacteria in obese mice compared to lean mice. The obese mice had more pro-inflammatory and fewer anti-inflammatory species than lean mice. The imbalance led to accelerated knee OA due to systemic inflammation and macrophage migration to the synovium. Interestingly, they found that oligofructose, a non-digestible prebiotic fibre, can help restore a normal lean gut microbiota in obese mice. The restoration of lean gut microbes was “associated with reduced inflammation in the colon, circulation and knee and protection from OA”.
Obviously one could wonder whether these findings apply to humans. About a year ago Dai et al. published the results of long-term studies on around 6000 people. Their findings consistently showed that higher total fibre intake was related to a lower risk of getting symptoms of knee OA!
Hoffman et al., from Marquette University in Wisconsin, have recently studied the effects of artificial sweeteners on rat physiology. They found that the consumption of aspartame (E951) or acesulfame potassium (E950) can lead to vascular impairment and changes in fat metabolism “that may be important during the onset and progression of diabetes and obesity”.
Research by Sen et al. presented at the 100th annual meeting of the Endocrine Society has shown that the low-calorie sweetener sucralose (E955) can have adverse health effects. Sucralose was found to promote more fat deposits within cells. It may cause this by increasing the transport of glucose into cells and overexpressing fat-producing genes. Another potential mechanism may be the promotion of oxygen radicals. These extremely reactive particles cause inflammation and facilitate the accumulation of fat within cells.
The researchers comment that these effects are “more pronounced in overweight and obese people rather than their normal weight counterparts because they have more insulin resistance and may have more glucose in their blood“.
A few months ago Terenteva et al. published their research findings on the effect of acupuncture in a group of middle-aged individuals with hypertension. Forty five adults with hypertension were randomly assigned to either an acupuncture group or a control group. The acupuncture group received 3 sessions of acupuncture per week for 8 weeks. The following points were needled bilaterally for 20 mins: St36, St37, Pc5, Pc6, Liv3, Sp4, and LI11.
The researchers found that acupuncture “resulted in beneficial reductions of aortic hemodynamics and arterial stiffness”. “Acupuncture decreased brachial systolic blood pressure (SBP) and diastolic blood pressure (DBP) by approximately 10 and 6 mmHg, respectively.” It also reduced aortic SBP by 10 mmHg. Although these effects seem small, they can decrease cardiovascular risk by over 30%.
The mechanisms behind the effects are thought to come from an increase in secretion of vasodilators (nitric oxide) and a decrease in secretion of vasoconstrictors (endothelin-1, angiotensin II). Modulation of the autonomic nervous system by decreasing sympathetic activity may also play a part.
Intermittent fasting (IF) is proven to have beneficial effects on aging, cancer, cardiovascular diseases and neurodegenerative diseases. However, it isn’t known whether the benefits of IF are due to caloric restriction (CR), as with fasting, or whether they’re due to changes in eating pattern. Recent studies have discovered that the browning of white fat can improve insulin sensitivity and energy expenditure by producing heat. Both exercise and cold exposure have been shown to transform white fat into brown fat.
A recent study by Kim et al. from the University of Toronto looked into the mechanisms underlying intermittent fasting’s effects on health. They separated mice into 2 groups: an IF group and a control group. The IF group was not fed for 1 day and then fed for 2 days in a row whereas the control group was fed daily. This went on for 4 months. By the end of the study, both groups had been fed the same amount of calories. After 4 months, the IF mice weighed significantly less and had increased insulin sensitivity and a more stable glucose metabolism. Additionally, they had a lower proportion of white fat because it had been converted into brown fat. The IF mice had higher levels of adipose vascular endothelial growth factor (VEGF). VEGF helps form new blood vessels and activates adipose macrophages (white blood cells) which are critical for the browning of white fat and heat production. Interestingly, IF led to the browning of visceral white fat while cold exposure leads to the browning of subcutaneous white fat.
The authors note that health is not solely about “what and how much” we eat but also “when and how often”.
Earlier this year Ural et al, from Yildirim Beyazit University Medical School in Ankara, studied the effects of acupuncture on patients with lateral epicondylitis/epicondylopathy (LE). Lateral epicondylitis or tennis elbow, as it’s more commonly known, is an overuse injury that leads to pain on the lateral aspect of the elbow and/or forearm. It usually affects people aged 40 or over. Treatment can include rest, NSAIDS, bracing, physiotherapy, shockwave therapy, steroid injections, platelet-rich plasma injections, Botox injections or surgery.
Diagnostic ultrasound of the common extensor tendon (CET) in people with LE can reveal oedema, bone irregularities and increased CET thickness. Common extensor tendon thickness provides information on the severity and progress of LE.
The authors randomly split 41 patients with LE into 2 groups. The control group was advised to rest and prescribed NSAIDS, exercise and bracing. The acupuncture group received the same intervention as the control group but with acupuncture in addition. The patients were offered 10 sessions (25 min each) of acupuncture over a period of 4 weeks. Six acupoints (LI4, LI10, LI11, Lu5, SJ5 and one Ah Shi point) were used and the needles were inserted into muscle and stimulated manually to achieve deqi (needling sensation). The assessments prior to and following the course of treatment consisted of a subjective pain evaluation, pressure pain threshold testing, a function questionnaire (Duruoz Hand Index) and an ultrasound evaluation of CET thickness.
Results showed that pain and function scores improved in both groups. Whereas pain pressure thresholds and CET thickness decreased in the acupuncture group only. Improvements in pain, function, pain pressure threshold and CET thickness were significantly higher in the acupuncture group.
The authors conclude that “acupuncture treatment not only reduces pain but improves the tendon morphology in LE patients.”
Helene Langevin is a professor at Harvard Medical School and at The University of Vermont College of Medicine. She is also the director for the Osher Center for Integrative Medicine. Her lab has conducted a lot of interesting research on connective tissue. I’ve summarised some of the findings that relate to the effects of stretching on connective tissue (fascia).
Studies from her lab have shown that stretching had beneficial effects on chronic inflammation in rats. They noted increases in stride length, decreased pain and decreased macrophages (inflammatory cells). Both active and passive stretching were effective and had an effect on acute and chronic phases of inflammation. Stretching decreases pro-inflammatory mediators and increases pro-resolving mediators such as Resolvin, which is synthesised from omega-3 fatty acids.
A thicker thoracolumbar fascia has been identified in some people with low back pain. And the decreased mobility of the fascial layers is thought to stem from adhesions between the layers. Stretching can decrease connective tissue adhesions (fibrosis) by decreasing collagen formation.
Additionally, links have been found between chronic inflammation, fibrosis and cancer. In summary, stretching can have beneficial effects on inflammation, pain, function and even the predisposition to certain types of cancer!
A few months ago Ural et al, from Yildirim Beyazit University Medical School in Ankara, published an interesting paper looking into the effects of acupuncture on carpal tunnel syndrome (CTS). Their work was published in Evidence-Based Complementary and Alternative Medicine.
CTS affects more women than men and has a prevalence of 1-5%. Causes include overuse of the hand, diabetes, rheumatoid arthritis, hypothyroidism and pregnancy. Symptoms can include pain numbness and tingling of the first 3-4 fingers, as well as weakness and wasting of the hand muscles supplied by the median nerve. Some of the commonly used treatments are rest, non-steroidal anti-inflammatory drugs, splinting, steroid inject injections, vitamin B6 supplementation, physiotherapy and eventually surgery. The cross-sectional area (CSA) of the median nerve has been found to increase in association with the severity of CTS. In fact, this increase in CSA is so reliable that it can be used to diagnose CTS or predict the need for surgery.
Ural et al recruited 27 female patients with mild to moderate CTS. On average, their symptoms had lasted about 1.5 years. They were randomised into an acupuncture group and a control group. Both groups wore a night wrist splint for 4 weeks. In addition to the night splint, the acupuncture group received 10 sessions of acupuncture over 4 weeks. Nine acupuncture points were used and the needles were retained for 25 minutes. Evaluations of hand function (DHI and DASH) and pain (VAS), electrophysiological tests and ultrasound measurements of CSA were taken before and after treatment.
The results showed that symptom severity, hand function and electromyographic measurements improved in both groups but improvements were significantly greater in the acupuncture group. In the acupuncture group, pain decreased by just under 50% (from 9/10 to less than 5/10), and hand function measurements improved by 15-22%. These are impressive results when we consider that they took place over a month and that patients had been symptomatic for 1.5 years prior to that. CSA of the median nerve was unchanged in the control group but significantly reduced in the acupuncture group (8% reduction). The authors believe that this is the first time the effect of acupuncture on median nerve CSA in patients with CTS has been demonstrated.
Ural et al conclude that “acupuncture improves not only clinical and electrophysiological findings but also morphological features in patients with CTS”, however “the relationship between change of CSA and electrophysiological changes was not correlated. The small sample size of our study may cause this result”. They suggest confirming the results in future studies with larger sample and long-term monitoring.