The Mediterranean and Paleo Diets may rank among the healthiest options around.
At least, that's the picture painted by epidemiological evidence, lab studies, and many anecdotal accounts.
Greens and animal proteins feature in both diets, with protein predominating in the Paleo plan.
But there are substantial distinctions to be made among animal proteins (meat, poultry, and fish).
Fish looks like the ideal protein source, thanks to its omega-3 fatty acids and vitamin D, and the evidence linking fishy diets to heart, joint, immune, and brain health.
(We should note that saturated fat and cholesterol from meat and poultry doesn't harm most people's hearth health. The only apparent exceptions are people whose genetic profiles can render them problematic.)
What is osteoarthritis?
Osteoarthritis or OA is the “regular” kind of arthritis that comes with age, and affects people in varying ways.
OA can be mild or severe, and may affect different joints at different ages, depending on a person's occupation, lifestyle, and genetics.
The condition is characterized by breakage or loss of cartilage … the hard, slippery connective tissue that covers the ends of bones where they meet to form a joint.
According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, OA afflicts 27 million Americans over the age of 25, with most patients being over age 50.
Younger people can develop OA, usually as the result of a joint injury, malformation, or genetic defect, but it OA becomes more common with age.
Before age 45, more men than women have osteoarthritis; after age 45, it is more common in women.
It's also more likely to occur in people who are overweight and in those with jobs that stress particular joints.
About one in five people over the age of 45 has osteoarthritis in their knee.
There is no cure or effective treatment other than pain relief, which is often inadequate (or causes adverse gastric effects), or joint replacement.
Exercise and weight control can improve OA symptoms and reduce the chances of the disease progressing.
But no research has yet proven that diet can contribute to prevention or treatment … although greens and garlic are linked to lower risk (Williams FM et al. 2010).
Now, two studies suggest that diets rich in fish and cruciferous vegetables may help keep arthritis at bay.
Studies see joint benefits from fish and cruciferous greens
Separate studies conducted in the U.S. and the United Kingdom (UK) provide more evidence of complementary health benefits from diets featuring greens and fish.
In both cases, the evidence involves these disparate foods' effects on osteoarthritis … the very common joint disorder described in our sidebar, “What is osteoarthritis?”.
Study #1 – Omega-3s may help allay arthritis
The results of a new rodent study from Duke University suggests that omega-3 fatty acids from seafood or supplements may slow the progression of osteoarthritis (Wu CL et al. 2014).
While scientists know that obesity is a key risk factor for osteoarthritis, it's not been clear how the two were related.
They've presumed that the heavier a person is, the more likely they are to wear out their joints.
But this couldn't explain OA in the hands, which don't bear weight … a mystery that led to the Duke study.
The Duke researchers studied mice who had osteoarthritis in the knee, and gave them one of three diets:
- Rich in saturated fat
- Rich in omega-6 fatty acids
- Rich in omega-6 fatty acids, with a small dose of omega-3 fatty acids
The Duke team found that overweight mice given supplemental omega-3 fatty acids had healthier joints than those fed diets high in saturated fats and omega-6 fatty acids.
The results suggest that dietary fats – not just excess body weight – may play important roles in osteoarthritis.
“While omega 3 fatty acids aren't reversing the injury, they appear to slow the progression of arthritis in this group of mice,” said senior author Farshid Guilak, Ph.D. “In fact, omega-3 fatty acids eliminated the detrimental effects of obesity [on knee joints] in obese mice.” (DUHS 2014)
“Our results suggest that dietary factors play a more significant role than mechanical factors in the link between obesity and osteoarthritis,” said professor Guilak.
The researchers are working to translate their findings to humans.
Study #2 – Broccoli and its cruciferous cousins vs. OA
Last year, research led by the UK's University of East Anglia suggested that a compound found in broccoli could be key to preventing or slowing the progress of osteoarthritis (Davidson RK et al. 2013).
The researchers set out to test the effects of a diet enriched with sulforaphane – the sulfur compound released when you eat cruciferous vegetables such as Brussels sprouts and cabbage, but particularly broccoli.
(Other cruciferous greens include cauliflower, cress, bok choy, kale, collard greens, kohlrabi, arugula, Napa/Chinese cabbage, turnip, wasabi, daikon, radish, and mustard greens)
Previous research indicates that sulforaphane possesses anti-cancer and anti-inflammatory properties, but this was the first significant study of its joint health effects.
The UK team discovered that sulforaphane also blocks enzymes that cause joint destruction by blocking a molecule known to cause inflammation.
But they needed to test whether the compound made its way into joints in amounts sufficient to halt cartilage damage and alleviate OA symptoms.
The UK team fed mice fed one of two diets:
As hoped, the mice fed the diet rich in sulforaphane showed significantly less cartilage damage and osteoarthritis than the control group.
The UK researchers seek to conduct a small clinical trial in osteoarthritis patients scheduled for knee replacement surgery, to see if eating broccoli has similar effects on human knee joints.
As lead researcher Ian Clark, Ph.D., said:
“The results from this study are very promising. We have shown that this works in the three laboratory models we have tried, in cartilage cells, tissue and mice. We now want to show this works in humans. It would be very powerful if we could.” (UEA 2013)
Stay tuned for the results of any follow up research conducted by the Duke and UK teams.
- Baker KR, Matthan NR, Lichtenstein AH, Niu J, Guermazi A, Roemer F, Grainger A, Nevitt MC, Clancy M, Lewis CE, Torner JC, Felson DT. Association of plasma n-6 and n-3 polyunsaturated fatty acids with synovitis in the knee: the MOST study. Osteoarthritis Cartilage. 2012 May;20(5):382-7. doi: 10.1016/j.joca.2012.01.021. Epub 2012 Feb 4
- Cai A, Hutchison E, Hudson J, Kawashima Y, Komori N, Singh A, Brush RS, Anderson RE, Sonntag WE, Matsumoto H, Griffin TM. Metabolic enrichment of omega-3 polyunsaturated fatty acids does not reduce the onset of idiopathic knee osteoarthritis in mice. Osteoarthritis Cartilage. 2014 Jul 4. pii: S1063-4584(14)01156-X. doi: 10.1016/j.joca.2014.06.033. [Epub ahead of print]
- Davidson RK, Jupp O, de Ferrars R, Kay CD, Culley KL, Norton R, Driscoll C, Vincent TL, Donell ST, Bao Y, Clark IM. Sulforaphane represses matrix-degrading proteases and protects cartilage from destruction in vitro and in vivo. Arthritis Rheum. 2013 Dec;65(12):3130-40. doi: 10.1002/art.38133.
- Duke University Health System (DUHS). Omega 3 Fatty Acids Lessen Severity of Osteoarthritis in Mice. July 11, 2014. Accessed at http://corporate.dukemedicine.org/news_and_publications/news_office /news/ omega-3-fatty-acids-lessen-severity-of-osteoarthritis-in-mice
- Green JA, Hirst-Jones KL, Davidson RK, Jupp O, Bao Y, MacGregor AJ, Donell ST, Cassidy A, Clark IM. The potential for dietary factors to prevent or treat osteoarthritis. Proc Nutr Soc. 2014 May;73(2):278-88. doi: 10.1017/S0029665113003935. Epub 2014 Feb 26.
- Knott L, Avery NC, Hollander AP, Tarlton JF. Regulation of osteoarthritis by omega-3 (n-3) polyunsaturated fatty acids in a naturally occurring model of disease. Osteoarthritis Cartilage. 2011 Sep;19(9):1150-7. doi: 10.1016/j.joca.2011.06.005. Epub 2011 Jul 1.
- Rosenbaum CC, O'Mathúna DP, Chavez M, Shields K. Antioxidants and antiinflammatory dietary supplements for osteoarthritis and rheumatoid arthritis. Altern Ther Health Med. 2010 Mar-Apr;16(2):32-40. Review.
- University of East Anglia (UEA). Broccoli could be key in the fight against osteoarthritis. August 28, 2013. Accessed at http://www.uea.ac.uk/mac/comm/media/press/2013/ August/broccoli-osteoarthritis-research-sulforaphane
- Wang Y, Wluka AE, Hodge AM, English DR, Giles GG, O'Sullivan R, Cicuttini FM. Effect of fatty acids on bone marrow lesions and knee cartilage in healthy, middle-aged subjects without clinical knee osteoarthritis. Osteoarthritis Cartilage. 2008 May;16(5):579-83. Epub 2007 Oct 15.
- Williams FM, Skinner J, Spector TD, Cassidy A, Clark IM, Davidson RM, MacGregor AJ. Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action. BMC Musculoskelet Disord. 2010 Dec 8;11:280. doi: 10.1186/1471-2474-11-280.
- Wu CL, Jain D, McNeill JN, Little D, Anderson JA, Huebner JL, Kraus VB, Rodriguiz RM, Wetsel WC, Guilak F. Dietary fatty acid content regulates wound repair and the pathogenesis of osteoarthritis following joint injury. Ann Rheum Dis. 2014 Jul 10. pii: annrheumdis-2014-205601. doi: 10.1136/annrheumdis-2014-205601. [Epub ahead of print]