Topical Application

How effective is sesame oil when used topically? In a clinical placebo-controlled double-blind study in an Iranian hospital, patients with traumatic injuries of the limbs were randomized to rub in oil made from tahini (sesame paste) or conventional cooking oil. Compared with the placebo group, the sesame group had reduced pain after 48 hours, and the sesame oil even helped prevent skin discoloration from bruising. So does it help to rub sesame oil onto arthritic knees?

In a head-to-head comparison of topically applied sesame oil and the leading topical NSAID, a one-percent diclofenac sodium gel like Voltaren, the sesame oil was similarly effective for pain and some measures of function, but the NSAID gel reduced stiffness better.

Flaxseed

Are there other topical treatment methods? As an experiment, researchers in Turkey randomized people with hand osteoarthritis to treatment with a warm flaxseed poultice. For one week, participants received once daily a warm mixture of flaxseed and water applied to the hands, which were then wrapped with gauze and kept warm for 20 to 30 minutes with a towel and a hot-water bottle. Compared with participants in the control group, who did nothing, the flaxseed group experienced significant pain relief and improved function. How do we know the benefit came from the flaxseed and not from the heat and pressure? The study had three groups: Participants were randomized to receive the flaxseed wrap, a warm wrap without flaxseed, or, in the control group, nothing—and the flaxseed group did significantly better even compared to the warm-compress group in terms of pain relief and functional improvement.

Does flaxseed oil also work, which has been used medicinally for more than 1000 years? In a randomized double-blind study, 100 patients with mild to moderate carpal tunnel syndrome rubbed either five drops of flaxseed oil or a placebo onto the back of the wrists twice daily. Compared with the placebo group, in the flaxseed oil group not only did pain and function improve significantly, but nerve conduction velocity did as well, suggesting an alleviation of nerve damage. And that for about a dollar a month. It’s time to rub some arthritic knees with flaxseed oil!

In another randomized placebo-controlled clinical double-blind study, participants rubbed 20 drops of flaxseed oil or a paraffin-oil placebo onto their knees three times daily for six weeks. And again, the flaxseed beat the placebo across the board—overall symptoms, pain, quality of life, and activities of daily living, as well as sport and recreation function. In writings of traditional Persian medicine, such as the Canon of Medicine, completed around the year 1012, topical application of flaxseed oil was recommended to relieve joint pain. It only took 1000 years for it finally to be studied.

Extra Virgin Olive Oil

The attribution of a “remarkable anti-inflammatory effect” to olive oil is based on laboratory experiments with rodents, but a systematic review with meta-analysis could not find any anti-inflammatory effect of olive oil. As I show in see.nf/oliveoil, in humans olive oil may be no better than butter with regard to inflammation, and in any case worse than coconut oil. But that applies to olive oil taken orally. With topical application, it may be different.

Patients with knee osteoarthritis were randomized to use regular olive oil or an NSAID gel for a month. The olive-oil group was instructed to apply one gram—less than a quarter teaspoon—of oil three times a day. That cost less than three cents a day, and it worked! The regular olive oil reduced pain significantly better than the medication. A study on rheumatoid arthritis came to a similar conclusion, where topical application of extra virgin olive oil outperformed rubbing in an NSAID gel or nothing at all (a “dry massage”).

Low Back Pain

In the second half of the 20th century, low back pain became one of the biggest problems for public health systems in the Western world. In 84 percent of the population, low back pain occurs at some point over the course of life; in about one in five it is chronic, and one in ten is rendered unable to work by it. It is an epidemic that is partly amplified by the obesity epidemic.

Carrying excess weight is not only a risk factor for low back pain, but also for sciatica, disc degeneration, and herniated discs. As with arthritis, this may be due to the combined effect of heavy loads on the joints and the higher inflammation and cholesterol levels associated with greater body weight. Autopsy studies show that the lumbar arteries that supply the spine can become clogged by atherosclerosis, and as a result the discs in the low back no longer receive oxygen and nutrients.

In see.nf/backpain I cover the topic in detail, and there you can also see images of the cholesterol-laden plaques that clog the openings to the spinal arteries. To become mobile again, perhaps one should pump blood back into the low back. Unfortunately, that has never been studied. Clinical trials have shown that better nutrition can slow the progression of coronary heart disease and improve blood flow again in peripheral arteries in the legs and in pelvic arteries in erectile dysfunction, but unfortunately there is still no randomized, controlled trial on improving disc degeneration or back pain by changing diet and lifestyle habits.

Dietary Supplements

In recent years, cannabis use among older people has increased dramatically. So far there are no signs of negative effects on cognitive ability or the mental health of the population with low-dose, short-term medical cannabis use. The evidence that alcohol is harmful is undoubtedly much stronger. But is cannabis also effective? Does a joint help the joints?

In a case report on osteoarthritis pain, a small, temporary effect of oral administration of cannabidiol oil (CBD) was found, which could also have been just a placebo effect. As of 2021, there were no randomized controlled trials of CBD for osteoarthritis. Unfortunately, researchers found that it did no more than a placebo for pain or sleep quality, depression, or anxiety.

Fish oil is another common dietary supplement that does nothing. A systematic review with meta-analysis of the five randomized controlled trials found that it has no statistically significant effect. However, the most commonly used dietary supplement for osteoarthritis is glucosamine.

Glucosamine

In see.nf/glucosamine I discuss glucosamine supplements in detail. In summary, there are substantial contradictions in the clinical research literature as to whether it works at all, with industry funding having the strongest influence on study results. That led the American College of Rheumatology to issue a strong recommendation against the use of glucosamine in the current guidelines.

Chondroitin

As I note in see.nf/chondroitin, the American College of Rheumatology also issues a strong recommendation against chondroitin, since the best studies find a “minimal or nonexistent” benefit. The only study ever published on prescription chondroitin and glucosamine supplements in pharmaceutical-grade quality found that they significantly worsened osteoporosis pain compared with a placebo.

Collagen

Nearly 1000 years ago, a medieval nun suggested eating gelatin for joint pain. When collagen was tested in multicenter, randomized placebo-controlled double-blind studies, unfortunately it did not appear to work. (Gelatin is basically just cooked collagen.) I discuss all the studies in see.nf/collagenjoints. The few that found a benefit were challenged by critics.

A comprehensive systematic review from 2022 suggests that more studies were not conducted because collagen supplements apparently had so many side effects.