Ankylosing spondylitis (AS) is a chronic inflammatory condition and a type of arthritis. It usually causes pain, stiffness, and reduced mobility in the spine. It can also affect other joints. Some people may find symptom relief by making dietary changes, though evidence is limited.

There is currently no cure for ankylosing spondylitis. However, getting an early diagnosis and using appropriate management techniques can help a person cope with the symptoms and reduce their risk of complications.

One 2018 review advises that only very limited evidence supports a link between diet and AS. Many of the studies were too small and unreliable to confirm any conclusions.

However, people with AS can try using diet alongside conventional treatments to reduce the symptoms. Unless a person has food intolerances or allergies, these dietary changes should be safe to try.

This article discusses how dietary choices can impact AS, which foods to eat and avoid, and the complications that this condition can trigger.

A supermarket stand consisting of vegetables to eat with AS.Share on Pinterest
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Although there is no specific diet for people with AS, consuming certain foods may help people manage symptoms of the condition.

Different foods can affect a person’s body weight, for example, and they might also play a role in inflammation.

The sections below cover diet’s role in AS in more detail.

AS and weight management

The Spondylitis Association of America notes that maintaining a moderate weight is important for people with AS, as excess weight places stress on the bones and joints of the body. This can make the symptoms worse.

Diet and inflammation

Adopting an anti-inflammatory diet may help reduce inflammation in the body. The foods in this type of diet are similar to those of the Mediterranean diet.

The Arthritis Foundation recommends that people with rheumatoid arthritis (RA) follow an anti-inflammatory diet. These foods may also benefit those with AS, which is a similar inflammatory condition.

The following foods may help reduce inflammation.

Omega-3 fatty acids

A 2017 review indicates that a diet high in these essential fats has a consistent but modest positive effect on joint inflammation associated with RA.

The following foods are good sources of omega-3 fatty acids:

  • chia seeds
  • fatty fish, such as salmon, sardines, and tuna
  • flaxseed
  • flaxseed oil
  • walnuts

A 2020 review notes that more research is necessary to confirm how effective omega-3 fatty acids are for reducing inflammation in people with AS. However, the authors note that older studies, such as a small clinical trial in 2006, found that high doses of omega-3 fatty acid supplementation may decrease the disease activity of AS.

Whole grains

Whole grains are high in fiber and nutrients. Examples of whole grains include:

According to a 2018 meta-analysis, whole grains may also help reduce inflammation across the body.

However, some people may find that grains containing gluten — such as barley, wheat, and rye — trigger their AS symptoms.

Anti-inflammatory herbs and spices

Certain herbs and spices may also be anti-inflammatory, including:

  • Garlic: Some compounds in garlic exhibit anti-inflammatory properties, according to a review from 2015.
  • Ginger: People have used ginger as an anti-inflammatory remedy for centuries. 2015 research notes that gingerols, a major compound in ginger, can help reduce arthritis and pain.
  • Turmeric: One of the main components in turmeric is curcumin, which is a compound that may help reduce inflammation.

Eating plenty of fruits and vegetables, alongside foods containing calcium and vitamin D, may benefit those with AS.

Fruits and vegetables

Eating a variety of fruits and vegetables each day ensures a high intake of many of the vitamins and minerals necessary for overall health. These foods also tend to be low in calories and high in fiber.

The National Axial Spondyloarthritis Society (NASS) of the United Kingdom recommends eating fruits and vegetables of different colors. These contain a wide array of antioxidant compounds that help protect against disease.

Calcium-rich foods

AS weakens the bones, which is why calcium-rich foods are so important. Calcium is essential for improving bone strength.

Food sources high in calcium include:

  • dark leafy greens, such as watercress and kale
  • broccoli
  • fortified plant milks
  • almonds
  • low fat dairy products
  • canned sardines with bones
  • Chinese cabbage
  • fortified tofu
  • fortified cereals

Vitamin D

Vitamin D allows the body to absorb calcium and is another vital nutrient for healthy bones.

One 2015 review reports that higher levels of vitamin D are associated with a lower risk of developing AS. Also, people with higher vitamin D levels are less likely to have symptoms related to the condition.

The body gets vitamin D from sun exposure and foods such as:

  • fish and seafood
  • egg yolk
  • cod liver oil
  • fortified products, such as juices, cereals, dairy, plant-based milk, and tofu

Foods that trigger inflammation may worsen AS symptoms. These foods include:

Sugar

According to one 2018 systematic review, added sugar and refined foods can lead to inflammation in the body.

As a result, those with AS may wish to reduce the amount of sugary foods and beverages they consume, including:

  • desserts
  • candy
  • pastries
  • sodas
  • juices

Salt and high sodium foods

In 2014, researchers found a connection between high salt intake and the production of an inflammatory cell that has links to autoimmune conditions, such as AS.

Although a low sodium diet cannot reverse AS, reducing salt intake is a good idea to help manage the condition.

Red meat

Red meat contains certain compounds that can aggravate inflammation.

Eating less or no red meat may help reduce the symptoms of AS.

High fat foods

The Arthritis Foundation recommends limiting types of fat that cause inflammation, including saturated fats and omega-6 fatty acids.

Foods that contain saturated fats include:

  • pizza
  • red meat
  • cheese and full fat dairy products
  • processed foods

Excess consumption of omega-6 fatty acids may trigger the production of pro-inflammatory chemicals.

Foods that contain omega-6 fatty acids include:

  • vegetable oils, including corn, safflower, sunflower, and soy oils
  • mayonnaise
  • salad dressings
  • pastries
  • processed foods

People should try to avoid trans fats, which may be present in processed foods.

Manufacturers have now phased trans fats out of food due to regulations from the Food and Drug Administration (FDA). However, manufacturers are allowed to keep a small amount of trans fats in processed foods as long as it is less than 0.5 grams (g) per serving. If there is less than 0.5 g of trans fat in the product, the nutrition label is allowed to indicate 0 g of trans fat.

Wheat and gluten

Gluten-containing grains — such as wheat, rye, and barley — may contribute to inflammation in some people.

A gluten-free diet is helpful for some individuals with RA, and it may also benefit those with AS.

Alcohol

People with AS should try to limit their alcohol intake or completely avoid it.

Heavy alcohol use can affect bone mineral density and increase the risk of osteoporosis. Alcohol may also interact with AS medications and reduce nutrient absorption.

AS has links to inflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis.

Making certain dietary changes may improve the symptoms of these conditions.

Some recommendations for people with IBD include:

  • reducing the intake of high fat foods
  • limiting or avoiding alcohol
  • cutting back on dairy products

Adopting an anti-inflammatory diet may also help alleviate the symptoms of IBD.

Learn which foods to eat during a flare-up of Crohn’s disease.

The packaging of some dietary supplements may suggest that they could help people with AS. However, some supplements are of poor quality, and the body may not readily absorb them. Others may not have the effects they claim.

Some of the supplements that manufacturers suggest for AS demonstrate no proven benefits for the condition.

However, consuming probiotics may be helpful for people with AS. A disease-causing bacteria called Klebsiella may play a role in the development of the condition and is present in the bowel flora of those with AS.

Probiotics may alter the gut microflora to help reduce a person’s susceptibility to AS.

However, more research on humans is required to confirm the benefits of probiotics on AS.

It is usually safe to make dietary changes to manage the symptoms of AS, especially when a person does this alongside taking the medication or other treatments that a doctor has recommended.

However, low calorie, low fat, and low protein diets may not provide enough nutrients to support the immune systems of people with AS.

To ensure adequate nutrient intake, it is important to discuss any dietary changes with a doctor and dietitian beforehand. Certain foods and supplements can interact with medications.

Research does not indicate that managing AS through the diet is effective.

Foods that trigger pain and other symptoms of AS vary from person to person. Keeping a food diary for a month can help a person pinpoint any foods that seem to make their symptoms worse.

There are a number of different treatments other than diet for ankylosing spondylitis.

Physical therapy

Keeping active and regularly exercising may help prevent people’s spines from becoming stiff and painful. According to the Spondylitis Association of America, people with ankylosing spondylitis can benefit from four main types of exercise:

  • range of motion or stretching
  • aerobic or cardiovascular
  • strengthening
  • balance

A workout routine involving each of these types of exercises can help relieve symptoms.

NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly used type of medication to treat the pain and stiffness that comes from AS. NSAIDs relieve pain and reduce inflammation in the body.

Examples of NSAIDs include:

The high doses that people may require to treat AS can lead to significant side effects, including:

  • inflammation of the stomach lining
  • heartburn
  • sometimes ulcers and bleeding

People should always speak with a doctor before trying a new treatment.

Other treatments

Other treatment options for ankylosing spondylitis include:

  • sulfasalazine
  • methotrexate
  • disease-modifying antirheumatic drugs (DMARDs)
  • surgery
  • corticosteroids
  • biological treatments, such as anti-TNF medicine or monoclonal antibody treatment

Below are some frequently asked questions about ankylosing spondylitis and diet:

Can a vegan diet help reduce inflammation?

Plant-based diets can influence inflammatory processes and therefore may be beneficial in reducing inflammation.

One 2022 study looked at people with systemic lupus erythematosus, a type of chronic inflammatory autoimmune disease.

Those who incorporated more plant-based foods and limited processed foods and animal products reported improvements in their disease symptoms, including:

Authors of a 2019 review suggest that people who eat a vegetarian or vegan diet tend to lose weight more so than with other types of diet, which could influence inflammation.

Can a paleo diet help reduce inflammation?

The paleo, or Paleolithic, diet is based on the food patterns of human Paleolithic ancestors from about 2.6 million to 10,000 years ago. More research is required to determine the health benefits of this diet.

There is some evidence from a 2019 meta-analysis that suggests the Paleolithic diet may assist in managing:

  • weight
  • waist circumference
  • chronic diseases

Can a low starch help reduce inflammation?

Some people claim that a low starch diet may benefit people with AS. The theory goes that some types of gut bacteria can trigger the condition, and starch feeds these bacteria.

The evidence supporting a low starch diet is anecdotal, meaning that although it may work for some people, NASS cannot endorse the diet due to a lack of solid research.

A person can talk with a healthcare professional if they want to try a low starch diet to help with their symptoms of AS.

While managing AS with diet alone is not advisable, some people may find that certain foods trigger the symptoms of AS, and it can help to avoid them.

There is also no evidence to suggest harm if people make dietary changes, unless people have food intolerances or allergies. Therefore, people may make changes to their diet in order to see if certain foods help ease their symptoms.

However, they should talk with a doctor before doing so to ensure they will consume enough nutrients and calories to support their immune system and promote their overall health.