Millions of people in the U.S. experience joint pain, which can result from injuries, repetitive stress, or different types of arthritis—including autoimmune conditions like rheumatoid arthritis and psoriatic arthritis. Many are beginning to wonder whether their diet could be playing a role in triggering inflammation and discomfort in their joints.
Most of us know which foods cause generalized inflammation and which ones to limit or avoid as part of a healthy diet. These include industrialized vegetable oils, trans fats, refined sugars, processed foods, fried foods, excessive alcohol, and soda or other sugary drinks.
But there are additional foods that have been shown to trigger or exacerbate joint pain and arthritis for some people. Foods that are usually considered healthy. These are gluten grains and nightshade vegetables. Let’s talk about each one and why they might be a problem for some folks.
Gluten
If you’re dealing with joint pain that lacks a clear cause or struggling with arthritis that isn’t improving despite treatment, gluten and the inflammation it may trigger could be to blame. Increasingly, healthcare professionals are acknowledging the link between this widely consumed protein and joint-related issues.
How Does it Impact Joints?
Here’s what happens: in those with gluten sensitivity, consuming foods made with wheat, barley, or rye can cause the immune system to treat gluten as a threat. This immune response leads to inflammation that can extend beyond the digestive tract and affect other parts of the body.
But doesn’t a gluten sensitivity mean you have gut symptoms? Not always. In some cases, joint pain may be the main, or even the only noticeable, symptom with little to no digestive issues. An inflammatory reaction caused by gluten can affect connective tissues and tendons, soft tissue surrounding the joints, and the joint itself. This means there could be a large segment of folks with unexplained joint pain who are unaware that gluten is worsening their condition due to a gluten sensitivity. Yikes!
Keep in mind that, for some people, gluten doesn’t directly cause joint problems but rather worsens existing joint pain and makes it harder to manage using standard treatments.
What Are Some Symptoms to Watch For?
So, how can you recognize if your joint pain might be related to gluten sensitivity? Symptoms of gluten-related joint pain include:
- Joint pain
- Red or inflamed areas
- Swelling
- Decreased range of motion
- Stiffness, especially in the morning
- Back pain
- Sacroiliitis, a condition that causes pain in the lower back and buttocks.
These joint problems often occur in combination with other signs of gluten sensitivity, such as:
- Abdominal pain and bloating
- Excessive gas
- Constipation or diarrhea
- Fatigue
- Weight loss
- Iron deficiency anemia
- Skin rashes
- Vitamin deficiencies
- Muscle weakness
- Neurological symptoms like ataxia and “brain fog”
- Headaches
Notice that there are a myriad of symptoms for gluten sensitivity that do not involve digestion/gut health.
Who is at Risk?
Not everyone with joint pain should eliminate gluten.
The impact of gluten on joint pain seems to be more prevalent in those with autoimmune conditions, including arthritis-related autoimmune disease such as rheumatoid arthritis and psoriatic arthritis. This is because those with an autoimmune condition have a higher risk of developing celiac disease. For this reason, anyone with unexplained joint pain or arthritis that has not responded to treatment should be evaluated for celiac disease, especially if other autoimmune conditions are present.
What if I Tested Negative for Celiac Disease?
Even in the absence of celiac disease, people can still be sensitive to gluten without realizing it. In fact, whether a person has celiac disease or non-celiac gluten sensitivity, following a gluten-free diet dramatically improves arthritis symptoms, often in just 4-6 weeks! The most effective way to find out if you’re sensitive to gluten is to follow a gluten-free diet for a few weeks. If your symptoms improve during this time, it’s a strong indication that gluten may be the cause.
Although gluten sensitivity isn’t the cause of all joint pain, it could be the missing puzzle piece for folks dealing with unexplained inflammation and discomfort. The only way to know for sure is to try a strict gluten-free diet and observe whether your symptoms improve. For some, eliminating gluten may provide relief when other treatments haven’t been effective.
Nightshades
In addition to gluten grains, vegetables from the nightshade family may also contribute to worsening joint pain. However, unlike the myriad of research around gluten and arthritis, the research around nightshades is not as conclusive on the topic.
What Are Nightshades?
Before diving into it further, let’s first define what nightshade vegetables are. They are members of a group of plants that encompass around 2,500 species! However, only a relatively small handful of these are even edible. That list includes:
- Potatoes (although sweet potatoes are okay)
- Tomatoes and tomatillos
- Eggplant
- Goji berries
- Peppers (except black pepper/peppercorns)
- Pepper-derived spices such as cayenne, paprika, and chilli powder
Do They Play a Role in Joint Pain?
Some studies suggest that nightshades can trigger inflammation while other research shows they may actually have a positive effect on joint pain and inflammation. While there is little scientific evidence to support either side, anecdotal evidence shows that people with arthritis often experience a worsening of symptoms after eating nightshades.
Whether or not nightshades cause joint pain directly, there are other, more indirect routes this can take. In some people, nightshades can trigger a cascade of events that can lead to arthritis. Nightshades contain compounds called glycoalkaloids, which protects them from being eaten by insects and other predators. This compound is toxic to humans and has been listed as a culprit behind arthritis pain. However, glycoalkaloids are found in highest amounts in the leaves and stems of these plants, with much lower concentrations in the actual flesh or peel of what we eat. While these small amounts are not harmful when eaten in normal quantities, research shows that those with autoimmune diseases can be extra sensitive to glycoalkaloids such that a low-level exposure can increase intestinal permeability (also known as leaky gut).
What Does a Leaky Gut Have to Do With Arthritis?
In a word – Inflammation. Inflammation is the common connection among any/all chronic disease whether it’s found in the gut, the brain, the skin, or the joints. In fact, the suffix “-itis” literally means “inflammation.” When we have a leaky gut, foreign substances enter the bloodstream, cause an immune response, and trigger inflammation throughout the body. Where there is chronic inflammation there will be chronic health conditions, such as arthritis, cardiovascular diseases, neurodegenerative diseases, digestive disorders, diabetes, and autoimmune diseases.
Compromised gut function, as seen in a leaky gut, is a primary way in which inflammation is triggered. This connection is so strong that protecting and supporting our gut health is one of the most important things you can do to prevent (or reverse) chronic disease. Anything that harms our gut harms the rest of our bodies!
Should I Avoid Nightshades?
As we’ve seen, a compound found in nightshades seems to impact those with existing autoimmune conditions more so than the rest of the population. If you have any autoimmune disease it would be worth it to avoid nightshades for several weeks while assessing your symptoms. This also holds true if you have arthritis in addition to an autoimmune condition (even if it’s unrelated to joints).
Even if this doesn’t describe you, every person is unique and will respond differently to different foods. So, if you notice that your arthritis pain flares up after eating nightshades, consider eliminating them from your diet for a few weeks to see if it makes a difference. Then slowly introduce them back into your diet, allowing 2-3 days between each one. If your symptoms worsen at this point, it’s best to avoid nightshades for a few months before trying to reintroduce them again.
Of course, not everyone with joint pain who eliminates nightshades from their diet experiences relief. If you do well with nightshades and don’t notice a worsening of symptoms when eating them (or an improvement in pain when avoiding them), then it’s a safe bet that nightshades don’t negatively affect you and you can enjoy them as part of a whole foods diet.
Whether with gluten or with nightshades (or any other suspected food), the best place to start if you’re curious about their effect on you is to avoid them for a time and assess any changes in your symptoms. Doing an elimination trial is a risk-free and low-cost way to see if your inflammation and joint pain is triggered by your diet. What is there to lose?