Ever heard people say that cracking your knuckles causes arthritis? It turns out that’s a debunked myth. But arthritis does affect joints like your knuckles, and rheumatoid arthritis (RA) is one of the most common forms, affecting 1.2% of Canadians. One mineral that can help alleviate symptoms of RA is zinc.

A rogue immune system

The fascinating thing about RA is that it’s caused by the immune system—usually our body’s protection—attacking healthy tissue around the joints. It particularly affects synovial joints, or joints with a fluid-filled cavity that cushions the point where bones meet, like your knees, shoulders, elbows, and wrists. The resulting chronic inflammation slowly degrades the joints, particularly the synovial tissues surrounding them. And RA is often painful, ranging from a dull ache to being absolutely excruciating.

But why is my immune system after my joints?

Autoimmune conditions like RA, where your own immune system attacks your body, can be caused by genetics, your diet, or a range of environmental factors. But these conditions are often marked by some kind of immune system imbalance. For example:

• A weakening of natural killer (NK) cells, white blood cells that are your immune system’s frontline defences.
• An imbalance between the Th1 and Th2 sequences of chemical reactions in the body that produce pro-inflammatory and anti-inflammatory proteins. A stronger Th1 response than Th2 means more inflammation.
• Overstimulation of Th17 lymphocytes, another group of cells that can cause too much inflammation if not regulated.

Zinc is involved in each of these cellular processes. Basically, the more optimal your zinc levels, the better balanced your immune system, and the less susceptible you are to autoimmune diseases.

How to fight RA-induced inflammation

To fight the joint inflammation caused by RA, there’s one key enzyme and antioxidant to know: superoxide dismutase. SOD for short, it breaks down reactive oxygen species, the harmful chemicals that encourage inflammation in your joints and other tissues. Studies have shown that administering SOD directly into joints helps control RA locally. But ideally, you want your body to naturally produce optimal levels of this enzyme.

So what causes low levels of SOD? Low levels of zinc!

That’s why it’s very common for RA patients to be zinc deficient. And bringing their zinc levels back to normal reduces common RA symptoms like morning stiffness and joint swelling.

Keeping your zinc levels up is important for another reason: RA patients have a higher number of pro-inflammatory cytokines (proteins that drum up inflammation) in their bodies. That can deplete zinc levels further, which only worsens inflammation. It’s a vicious cycle you don’t want to get caught in.

Remodel your bones with zinc

RA destroys not only cartilage, bones, and joints but also the surrounding extracellular matrix (ECM). As its name implies, the ECM is the area outside cells. It functions as a kind of “scaffolding” for cells, and it’s where your bones are formed. The ECM is helped by matrix metalloproteinases (MMPs), enzymes responsible for breaking down bone and its structural components like collagen and gelatin. That’s actually a good thing in the right amount. If your bones were a brick wall, the MMPs would make more bricks available to build with.

To restore the ECM to health, we need a controlled number of MMPs working properly. The fact that they have the word “metal” in their name is a clue. They’re zinc-dependent!

Zinc is a key regulator of MMPs. So a zinc deficiency causes too many MMPs, which then degrade other ECM components like proteoglycans, glycoproteins, osteonectin, osteocalcin and collagen fibres—all of which help form healthy bones.

Increasing zinc in your diet

According to Health Canada, adults need 11mg of zinc per day. Making sure you’re getting your daily dose of zinc from foods like red meat, shellfish, and legumes such as chickpeas, lentils, and beans, will help prevent zinc deficiencies. And since zinc plays such an essential role in the immune system and keeping your bones and joints healthy and strong, having optimal levels of zinc will make you less susceptible to autoimmune diseases like rheumatoid arthritis.