Paul McCabe et al from the University of Manchester analysed data from the European Male Ageing Study and found that men with vitamin D deficiency at the start of the study were more than twice as likely to experience ongoing widespread pain over the next 4 years as those with high levels of vitamin D. It was noted that the men with chronic widespread pain were more likely to be physically active, obese, depressed and to have other health problems. Once these other factors were taken into account the link between vitamin D and pain disappeared.
However, John McBeth et al analysed data from the same study and found that even after adjusting for other health factors, pain remained moderately associated with increased odds of having low vitamin D levels. This is supported by a 5-year longitudinal study published last year by Laura Laslett et al in which vitamin D deficiency was found to predict incidence or worsening of knee pain and hip pain.
There seems to be a link between a deficiency of vitamin D and pain but could supplementation with vitamin D help to decrease pain? Between 2008 and 2010, Shreuder et al conducted a study in Holland and they did indeed find a small positive benefit (less pain and better function) after taking a high dose of vitamin D for 6 weeks.
What could the mechanism behind vitamin D and pain be? Tague et al found that vitamin D deficiency in rats can lead to a hyperinnervation of skeletal muscle which is likely to contribute to muscle hypersensitivity and pain.
Vitamin D is naturally present in a few dietary sources such as fish oils, mushrooms, eggs and liver. Other than supplements, sunlight exposure is the best source of vitamin D for most of people.
- Propecia: now used to promote hair growth in balding men but originally sold to treat prostate enlargement
- Viagra: now used to treat male erectile dysfunction but originally sold to treat hypertension and angina
- Play-Doh: now sold as molding clay for children but originally marketed as a wallpaper cleaner
- WD-40: now used as a mechanical lubricant but originally invented to protect nuclear missiles
Last week I read an article in Medical News Today that made me think glucosamine could be next on the list. Glucosamine has been used for years to treat joint pain and stiffness but Ristow and colleagues have explored a different use and published their findings in the April issue of Nature Communications. They fed glucosamine to roundworms and found that they lived about 5% longer than the control group. Encouraged by the results they then fed glucosamine to ageing mice. The mice were 100 weeks of age which is equal to around 65 years in human age. Amazingly, the lifespan of the mice on glucosamine was increased by 10% compared to the controls on a normal diet. This is equivalent to 8 extra years of human lifespan! The researchers found that glucosamine offered protection from diabetes by improving glucose metabolism.
How could this relate to humans? Well, a study by White and colleagues published a couple of years ago in European Journal of Epidemiology may answer that question. Over 77,000 people aged 50-76 years were followed for mortality for about 5 years. Glucosamine was linked to a significant decreased risk of death from cancer and a large risk reduction for death from respiratory diseases. Glucosamine and chondroitin use was associated with a decreased risk of total mortality.
There are no known side effects of glucosamine supplementation. If I wasn’t already taking glucosamine, I’d be heading straight for the shops!
Encarna Aguayo and colleagues from the Universidad Politécnica de Cartagena in Spain have published a study in the Journal of Agricultural and Food Chemistry that supports the use of watermelon juice to relieve post-exercise muscle soreness. They attribute the effect to the amino acid L-citrulline.
Osteoarthritis (OA) is a common source of joint pain, stiffness and swelling. It’s a leading cause of chronic disability and affects about 8 million people in the UK and 27 million in the US. OA leads to the gradual degeneration or wear and tear of joint surfaces and is often the cause of knee and hip replacements. Can nutritional supplements prevent or slow down the process? In my opinion, supplements can be separated into 2 groups: those that decrease inflammation and those that promote the regeneration of joint surfaces. I’d like to focus on the latter.
For quite a while, glucosamine, chondroitin and methylsufonylmethane (MSM) have been used to treat osteoarthritis.
Glucosamine contains glycosaminoglycans which are a major component of joint cartilage. The glucosamine that is available commercially is derived from the exoskeleton of shellfish. Although inconsistent results have been reported, in 2009, a team at the University of Aberdeen led by C Black reviewed the literature on the clinical effectiveness of glucosamine in slowing or arresting the progression of OA of the knee. Only trials that met stringent criteria were used. They found that there were ‘statistically significant improvements in joint space loss, pain and function for glucosamine sulphate and in 2 studies the need for knee arthroplasty (replacement) was reduced from 14.5% to 6.3% at 8 years follow-up’ . Another study found ‘a 50 % reduction in the incidence of osteoarthritis-related surgery of the lower limbs during a 5-year period’. In 2007 a the WHO Collaborating Center for Public Health Aspect of Osteoarticular Disorders at the University of Liege conducted a review of published studies that concluded that ‘glucosamine sulphate (but not glucosamine hydrochloride) and chondroitin sulphate have small-to-moderate symptomatic efficacy in OA, although this is still debated. With respect to the structure-modifying effect, there is compelling evidence that glucosamine sulphate and chondroitin sulphate may interfere with progression of OA’ . In other words, there is compelling evidence that glucosamine sulphate and chondroitin sulphate prevent joint space narrowing by promoting the regeneration of articular cartilage. Almost all trials have found the safety of glucosamine sulphate and chondroitin sulphate to be equal to placebo.
Chondroitin is also a glycosaminoglycan and a component of joint cartilage. Commercial chondroitin is derived from the cartilage of cows, pigs, shark, fish or birds. See above for results of research.
MSM occurs naturally in many primitive plants and in many foods and beverages. The mechanism of its action is uncertain but sulphur is thought to play a part. A literature review of MSM in the treatment of OA by a team at the University of Southampton showed that there was ‘positive but not definitive evidence that MSM is superior to placebo in the treatment of mild to moderate OA of the knee’. Last year an Israeli team led by EM Debbi published a study showing that, after taking MSM for 12 weeks, there was a small improvement in pain and physical function in patients with radiographic confirmed knee OA.
Recently ESM Technologies has funded research on the benefits of eggshell membranes. The eggshell membrane is just underneath the shell and surrounds the egg white. It’s interesting to note that in general, commercially funded trials show larger effects than industry independent trials.
Eggshell membrane or Natural Eggshell Membrane (NEM) as it is also known contains glucosamine, chondroitin and hyaluronic acid (also a glycosaminoglycan found in joints). In 2009, two papers were published (Journal of Clinical Interventions in Aging and Clinical Rheumatology) on the use of eggshell membrane to treat joint and connective tissue disorders. Both studies were led by Kevin Ruff and sponsored by ESM Technologies. The results were extremely encouraging and showed statistically significant improvements in pain, stiffness and flexibility. The positive results may be due to better bioavailability of joint sustaining compounds from eggshell membranes or possibly to researcher bias due to vested interests. This year, a study by the same author looked into the safety of NEM and concluded that it was safe for human consumption. Hopefully this will lead to independent research to look at the efficacy of NEM supplementation for joint disorders.
As we can see, there are several nutritional supplements that can aid the regeneration of joints. Here are the recommended daily dosages:
- Glucosamine Sulphate 1500 mg/day
- Chondroitin Sulphate 1200 mg/day
- NEM 500 mg/day
What are the best sources of omega-3 fatty acids? Before we delve into that, it’s important to distinguish between 3 types of omega-3 fatty acids:
- alpha-linolenic acid (ALA)
- docosahexaenoic acid (DHA)
- eicosapentaenoic acid (EPA)
Our bodies don’t produce ALA, so it’s essential to our diet. We can convert ALA into DHA and EPA but this is limited, so they’re required as well. In brief, we need all three. ALA is found in flaxseed oil (1:3) , canola oil (2:1), soybean oil (7:1), olive oil (3-13:1), butternuts, walnuts, edamame and chia seeds. EPA/DHA are found in oily fish (herring, sardines, mackerel, salmon, anchovies, trout and halibut). Surprisingly, EPA and DHA can also be found in meat and eggs but mainly when the animals were fed on grass rather than grain.
Although the previous post focussed on the anti-inflammatory effects of omega-3s, there are other benefits. They have been found to improve appetite, weight and quality of life in cancer patients. They stimulate blood circulation and decrease systolic blood pressure, reduce the risk of heart attack and help with varicose veins. Lastly, they improve brain function and help with depression and Attention Deficit Hyperactivity Disorder (ADHD). However, like most things in life, omega-3s should be taken in moderation…an excess of 3g of DHA/EPA per day could lead to an increased risk of bleeding, stroke, decreased blood sugar tolerance in diabetics and an increase in low density lipoproteins (LDL). Another concern is the presence of heavy metals and other fat soluble pollutants in fish…healthy eating is good but not simple! Fortunately the benefits outweigh the disadvantages.
The suggested intake of ALA is 1.1g/day (women) – 1.6g/day (men) and for EPA/DHA it’s 2 servings of fish per week (more for those with risk of heart disease).
Our diets have changed considerably over time. Today, diets in industrialised countries have a higher composition of saturated fat, trans fatty acids, omega-6 polyunsaturated fatty acids (PUFA) and a lower composition of omega-3 PUFA than ancestral diets. The ratio of omega-6 to omega-3 is around 15:1 and it’s thought that an optimum ratio should be about 1-4:1.
What’s the significance of this? Well, omega-6 PUFA and omega-3 PUFA have opposing effects on our bodies. Put simply, omega-6 PUFA are pro-inflammatory whereas omega-3 PUFA are anti-inflammatory. Omega-3 PUFA inhibit the metabolism of omega-6 PUFA into inflammatory cells. Inflammation is characterised by the cardinal signs: pain, redness, swelling, heat and loss of function. Although it’s a normal response to infection and injury…inappropriate inflammation can cause problems! Scientists have noticed that the change in our diets has coincided with an increase in inflammatory disease such as nonalcoholic fatty liver disease, cardiovascular disease, inflammatory bowel disease, rheumatoid arthritis, Alzheimer’s disease, etc.
Clinical studies have reported beneficial effects of increased omega-3 PUFA consumption in people with rheumatoid arthritis, inflammatory bowel disease and asthma. Less pain, fewer tender joints, a shorter duration of morning stiffness, a decreased use of non-steroidal anti-inflammatory drugs and an improved physical performance has been observed in people with rheumatoid arthritis. It has also been suggested that omega-3 supplements may be beneficial to patients in intensive care or post surgery. The grandmother’s remedy of taking cod-liver oil for arthritis now seems to make sense!
I would recommend eating foods rich in omega-3 PUFA or taking supplements for any musculoskeletal condition with inflammation and pain. What foods are rich in omega-3? Make sure to check in next week for the answer…