If you’re not worried about developing osteoarthritis, you should be. Osteoarthritis (OA) is the most common joint disorder in the world and the leading cause of disability in the elderly. In fact, once you reach 65 years old, you have a 50/50 chance of developing clinically diagnosed OA. If you’re between 45 and 64, you have a 30 per cent chance.1
Of course, understanding the cause of OA plays a large role in determining both how to treat and prevent the disease. The widely accepted risk factors include age, obesity, joint injury, genetics, gender, joint misalignment, and metabolic disorders.2-5 However, the concept that OA merely results from the wear and tear on a joint over time is being challenged by new emerging paradigms.
Along with these new paradigms comes new and exciting ways to prevent the disease in the first place – key among them can be found in the produce section of your local supermarket.
A new theory on the true cause of osteoarthritis
I came across one of the key new approaches to understanding the true causes of OA about 10 years ago when I met Dr. Cheras, an Australian medical professor, working in the field. His key theory is that OA is caused by the quality of your blood, just like cardiovascular disease. In fact, there is growing evidence from epidemiological studies suggesting that OA is linked to primary cardiovascular (CV) disease.6
A higher risk of cardiovascular death is associated with widespread OA, and one large study found that men with OA in any finger joint were 40 per cent more likely to die from cardiovascular disease.7 One study by Prof. Cheras found that the same risk factors that predict CV disease – especially those related to coagulation, clotting, and blood flow properties – also predict OA (but with a lower threshold).8
A crucial insight as to how changes in blood properties can increase the risk of OA emphasises the importance of the tiny blood vessels in the bone underlying the joint. According to one recent review, this could play a key role in the initiation and/or progression of OA.9 The disruption of micro-vascular blood flow in the bone under the joint (the subchondral bone) may reduce nutrient distribution to the joint cartilage. A restriction in blood supply may produce bone cell death, bone resorption, and the joint damage found in OA.
Another slightly earlier review suggested that vascular disease in the bone under the joint may accelerate the OA process.9 This is caused by either the lack of nutrition to the cartilage or because of the direct effect that restricted blood supply has on bone (depending if cartilage damage is a primary or secondary inflammatory event). So, vascular disease could also be highly relevant to the progression of OA.
That’s why I reacted with great excitement when an otherwise bland-looking research paper was published on the topic of diet and OA risk.
This was an epidemiological study of twins in the UK with osteoarthritis (OA).10 In the study, the consumption of non-citrus fruit and Allium vegetables (garlic, onions, and leeks) demonstrated a strong protective association for the development of OA of the hip joint. In contrast, French fries and roast potatoes were associated with a substantially increased risk. It’s highly likely that the Allium vegetables were preventing OA by improving the quality of the blood and circulation.
What AGE has to do with OA
This study ties into another interesting theory of the cause of OA: the effects of AGEs (advanced glycation end products) in initiating cartilage degeneration and inflammation. AGEs are well-named, as they are linked to many age-related diseases. They form when glucose in body tissues irreversibly binds to proteins, potentially rendering these proteins dysfunctional.
AGEs are formed in proportion to the amount of glucose present in body tissues, which in turn is related to how well insulin is working in the body (in other words, the degree of insulin resistance). AGEs would explain the association observed above with French fries and roast potatoes, since fried starchy foods are a rich source of dietary AGEs.
Also, excessive potatoes in the diet can increase the risk of insulin resistance by increasing body fat around the waist.
In support of this theory, increased severity of OA correlates with higher cartilage AGE levels.11 AGEs in cartilage trigger AGE receptors (RAGE) on inflammatory cells to increase catabolic activity, including production of cytokines and matrix-degrading enzymes, which degrade and break down cartilage.12 So the RAGE are also well-named as they can trigger a crescendo of inflammation in the body tissues.
The best diet for OA prevention
The accumulation of AGEs can be reduced by largely avoiding their highest dietary sources. These mainly include roasted, grilled and fried foods (especially nuts, French fries, packaged snacks such as crisps, all meats, chicken, fish and eggs (fried bacon and sausages are very high sources), cooking oils, and cheese.13 Marinating meat with either lemon juice or vinegar prior to roasting substantially reduces AGE formation. The low-temperature cooking techniques used in molecular gastronomy will also minimise AGE production.
In addition, you can reduce the formation of endogenous AGEs in body tissues by avoiding both insulin resistance and high glycaemic index/ glycaemic load diets that can lead to insulin resistance. That is a separate topic in itself, but herbs that can maintain good insulin sensitivity such as milk thistle (as the silymarin extract), gymnema, and Korean ginseng, together with those that can assist body fat loss such as coleus, can all be of value here. The result will be better insulin control – with less painful joints likely to be one of many indirect benefits.
As already noted, the observed benefits of Allium vegetables (especially garlic) in preventing OA could be due to the well-described effects of this herb on microcirculation and blood quality. Non-citrus fruit includes grapes and berries, which are rich in OPCs and anthocyanins, both known to benefit the microcirculation. Other key microvascular herbs that could help prevent OA include bilberry, gotu kola, grape and pine bark extracts, and Ginkgo biloba.
To your better health,
Nutrition & Healing
Volume 6, Issue 3 – March 2012
Full references and citations for this article are available in the downloadable PDF version of the monthly Nutrition and Healing issue in which this article appears.