Chapter 113
Strawberries
On the other hand, when mice were given green tea in their drinking water, they were less likely to develop arthritis, and their osteoarthritis progressed more slowly. In vitro, green tea was also able to protect human cartilage explants. The first and so far only clinical study on this was published in 2016. Patients with osteoarthritis of the knee were randomized to receive either the equivalent of about three cups of green tea per day plus an NSAID medication, or the medication alone. After four weeks, there was a significant improvement in osteoarthritis symptoms in the green tea group, especially in physical function. Unfortunately, it was an open-label study, meaning participants knew which group they were in, so placebo effects cannot be ruled out. Participants who drank two cups of peppermint tea daily for 16 weeks also reported an improvement in osteoarthritis symptoms, but here too there was no placebo control group, so it is not certain whether there was actually an effect.
In connection with beverages and osteoarthritis, soft drinks and milk, among other things, have been studied. Independent of body weight, soda drinking was associated with increased progression of knee osteoarthritis, but only in men, which calls this association into question. Milk, by contrast, was associated with less progression of the disease, but only in women, whereas cheese in a study in the United States was associated with greater progression. In a Dutch cross-sectional study, however, there was an association between cheese (but not milk) and less osteoarthritis.
In a comparative intervention study, soy protein outperformed milk protein, suggesting that soy milk is better for osteoarthritis patients, but we do not know whether this points to the benefits of soy or the potential harmfulness of dairy products. A study in Iran attempted to answer this question. Half of the milk-drinking participants with osteoarthritis were randomized to try to stop drinking milk. Among those who managed to do it, pain decreased significantly after three weeks. (A more precise study design would have replaced the milk with an identically tasting plant milk.)
Strawberries
If antioxidants have a protective effect, what about berries? Strawberries lower the level of the inflammatory mediator tumor necrosis factor (TNF) in the blood, but this does not necessarily translate into a clinical improvement. For example, cherry juice can reduce C-reactive protein (CRP), another marker of inflammation, but that does not help against osteoarthritis. Tart cherry juice “relieved the symptoms,” but not substantially more than a placebo drink without cherries (Kool-Aid). Cherries may help with gout, another type of arthritis, but failed in osteoarthritis. Likewise, pomegranate may help with rheumatoid arthritis, but pomegranate juice did not even beat a control group that did nothing in osteoarthritis, even though pomegranate extracts in a Petri dish appeared to protect cartilage.
Pomegranate juice, however, unlike strawberries, does not lower blood CRP levels. When diabetics were given strawberries for six weeks, their diabetes improved, and in addition their CRP levels dropped by 18 percent. Strawberries can even markedly downregulate pro-inflammatory genes and thereby reverse the growth of precancerous lesions. Even a single meal can help. So can strawberries relieve pain and inflammation in diagnosed knee osteoarthritis? Yes.
Obese men and women with osteoarthritis were randomized for twelve weeks to receive either the equivalent of about 600 deciliters of strawberries per day (as freeze-dried strawberry powder) or, in the control group, a placebo powder of the same color and taste. In the strawberry group, inflammation markers fell sharply, and there was a significant reduction in constant pain, intermittent pain, and total pain. From this the researchers concluded: “Our study shows that in adults with osteoarthritis, simple dietary interventions, i.e., adding berries, can have a significant impact on pain, inflammation, and overall quality of life.”
The strawberries cut the levels of the inflammatory mediator tumor necrosis factor in half, but the effectiveness of strawberries may not lie in their anti-TNF effect, because blueberries can also suppress TNF but, in a similar randomized osteoarthritis double-blind study, were no better than the control group's placebos.
Rose Hips
When thinking about which fruits might be helpful for osteoarthritis, you probably don't think of rose hips, the fruits of the rosebush. Typically, they are made into a somewhat fuzzy-tasting tea, and you can buy them dried and often unpackaged in natural foods stores.
There have been three randomized placebo-controlled double-blind studies of rose hips for osteoarthritis. Hundreds of men and women, most of whom had osteoarthritis of the knee, were randomized for three to four months to consume either 5 grams of rose hip powder per day, about one-third of a teaspoon, or a similar-looking placebo powder. Among those who, without knowing it, took the real rose hips, pain decreased significantly compared to placebo, similar to the pain reduction from NSAID medications, only without side effects.
Broccoli
How do vegetables fit into this? Broccoli is promising. Sulforaphane, the component in the broccoli family that presumably plays a key role in our health, protects human cartilage in the laboratory, but how do we know whether it even makes it all the way into the joints? We didn't know—until a group of British researchers had patients who were to receive a new knee joint eat broccoli in the two weeks before surgery and then found sulforaphane in the joint fluid during surgery (in contrast to patients who were supposed to avoid cruciferous vegetables).
In mice, sulforaphane reduces the severity of osteoarthritis, but it is only now being tested in humans. The randomized Broccoli in Osteoarthritis Study (BRIO) is currently investigating the effect of broccoli soup, and results should be available soon. Just ten days of eating broccoli can lower C-reactive protein (CRP) levels in smokers by 40 percent, but it is not yet known whether this leads to less knee pain and dysfunction. However, there are foods that have been shown to address the problem at its root: ginger and turmeric.
Ginger
In see.nf/ginger I cover the randomized controlled trials showing that as little as an eighth of a tiny spoonful of ginger powder can relieve pain in knee osteoarthritis and works as well as ibuprofen, while protecting rather than damaging the gastrointestinal mucosa. Ginger has famously been applied topically to painful joints for 1000 years, but the only controlled study to date on topical application examined men who placed ginger slices on the scrotum. The result: inflamed testicles healed three times faster in the ginger group.
Turmeric (Curcuma)
After study participants ate one and a half teaspoons of ginger powder daily for seven days, researchers drew their blood and dripped it onto cells in a Petri dish. Compared to blood from before the ginger week, the blood afterward suppressed the release of inflammatory mediators such as TNF. Turmeric has the same anti-inflammatory effect, although less than a tenth of a teaspoon a day is enough.
In 16 randomized controlled trials using various turmeric preparations, the effect of the spice for the treatment of knee osteoarthritis was investigated, starting at the equivalent of about half a teaspoon per day for up to 16 weeks. In eleven of the studies, turmeric was pitted against a placebo, and in the other five against NSAIDs. Compared to placebo, the turmeric extracts led to a significant reduction in knee pain and an improvement in physical function; against NSAIDs, they were roughly comparable but safer. A study on the topical use of a turmeric extract mixed with petroleum jelly was published in 2020, and it found substantial pain relief. It was supposedly a double-blind trial, but the placebo was plain petroleum jelly, so the color difference likely tipped off both the participants and the evaluators as to who belonged to which group. So if you want to make a turmeric pumpkin-pie smoothie like my self-created Okinawa blend, perhaps with a little ground ginger as well, I recommend drinking it rather than rubbing it on.