The ketogenic (keto) diet has gained immense popularity in recent years, becoming the most Googled diet of 2018. While primarily known for rapid weight loss, the keto diet has also been linked to improvements in certain medical conditions like diabetes and heart disease. This article delves into the potential relationship between the keto diet and gout, a type of inflammatory arthritis characterized by the build-up of uric acid crystals in the joints.
Gout is a common form of inflammatory arthritis affecting 4% of all American adults, according to the Arthritis Foundation. It develops when there's too much uric acid in the body, forming painful needle-like crystals in the joints. Managing gout typically involves a combination of medication, diet, and lifestyle changes. Medications include nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids to ease symptoms of acute attacks, as well as drugs to control uric acid levels and prevent future attacks.
Understanding the Ketogenic Diet
The keto diet is a very low-carb, high-fat diet designed to induce a metabolic state called ketosis. In ketosis, the body shifts from using glucose as its primary fuel source to burning fat, producing ketones as an alternative energy source. A classic ketogenic diet typically consists of 70-80% fat, 20% protein, and 5% carbohydrates. This metabolic shift results in decreased hunger and increased weight loss.
The Conflicting Evidence: Keto and Gout
The research on the effects of a keto diet on gout presents a mixed bag of results. While some evidence suggests potential benefits, other aspects of the keto diet might increase the risk of gout flare-ups.
Potential Benefits
- Reduced Inflammation: A 2017 study by researchers at Yale University explored how ketosis affects the NLRP3 inflammasome, a protein complex that triggers inflammation contributing to diseases like gout. Animal and human studies indicated that a keto diet resulted in less joint inflammation. Emily Goldberg, PhD, a postdoctoral fellow at Yale University, clarifies, "We are not trying to say that a ketogenic diet prevents or cures gout," but the research is promising.
- Weight Loss: Weight loss is an effective way to lower uric acid levels and prevent gout flare-ups. Since the keto diet promotes weight loss, it may indirectly benefit individuals with gout.
Potential Risks
- Increased Uric Acid Levels: The keto diet is often high in purine-rich foods, which the body breaks down into uric acid. Gout develops when there's too much uric acid in the blood, leading to the formation of needle-like crystals in the joints. A 2012 study found that people experience an increased risk of gout when they first enter into ketosis due to an increase in uric acid levels. However, the risk may be short-term and improve once the body adapts to being in ketosis.
Dietary Approaches: Keto vs. Low-Purine
A central aspect of managing gout is controlling uric acid levels. Since purines are metabolized into uric acid, a low-purine diet has been a traditional recommendation. However, a 2021 paper claims little evidence exists for the long-term sustainability and efficacy of low purine diets for gout.
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The Keto Diet and Purines
A typical ketogenic diet contains 30-35% protein, meaning it is not low in protein or purines. Foods high in purines and known to trigger gout flare-ups include red meat (beef, pork, and lamb), organ meat (liver, kidney, and sweetbreads), seafood (shellfish, tuna, and anchovies), high-sugar foods and beverages (pastries, candies, and sweetened beverages), and alcohol.
A Balanced Approach
Given the potential drawbacks of a high-purine keto diet, a more balanced approach may be beneficial. Choosing quality carbohydrates rather than avoiding them altogether may be a better route to take. Eating plenty of low-glycemic carbs - think legumes, dairy, and some fruits - was linked with reduced uric acid levels in a 2016 study from Johns Hopkins University School of Medicine.
What to Eat When You Have Gout
A diet that helps manage gout should focus on reducing uric acid levels and inflammation. Randall N. recommends "copious amounts of whole grains, plant-based protein, fresh vegetables and fruits, daily nuts, legumes, low-fat dairy, oily fish, and chicken and eggs in moderation."
Foods That May Help Lower Uric Acid
- Coffee: A 2015 review article suggests there’s evidence that coffee may lower the risk of gout flare-ups.
- Low-Fat Dairy Products: Milk and yogurt may be beneficial.
- Vitamin C: Vitamin C may also help reduce the risk of flare-ups.
- Cherry Juice: The juice can treat flare-ups by lowering the levels of uric acid in the body.
Other Lifestyle Changes
- Drink Plenty of Water: Water helps your kidneys flush out uric acid, shorten the duration of a flare-up, and reduce the severity of your symptoms.
- Exercise and Maintain a Healthy Weight: Weight loss lowers uric acid levels and your risk of heart disease and stroke, both of which are more common in people with gout.
Systematic Review and Meta-Analysis
A systematic review and meta-analysis of randomized control trials (RCT) investigated the effect of two nutritional interventions - the Dietary Approaches to Stop Hypertension (DASH) diet and the ketogenic diet (KD) - on serum uric acid (UA) concentrations. The analysis, which included studies up to March 2023, found 10 eligible RCTs that assigned adults to either a DASH diet (n = 4) or KD (n = 6) for at least 2 weeks and provided laboratory data on serum UA.
DASH Diet
The meta-analysis of the 4 DASH diet RCTs, with a total of 590 participants, revealed a significant decrease in serum UA after at least 4 weeks of interventions (mean difference (MD) = ‒0.25; 95% CI ‒0.4 to ‒0.1 mg/dL; p < 0.01; I2 = 0%). The DASH diet is comprised of fruit, vegetables, low-fat dairy products, and moderate proteins.
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Ketogenic Diet
The pooled meta-analysis of the 6 included RCTs of KD, reporting data of 267 participants, showed no significant changes in serum UA (MD = 0.26; 95% CI ‒0.47 to 0.98 mg/dL, I2 = 95.32%). However, a non-significant reduction of UA in the subgroup analysis of very low-calorie KD (VLCKD) studies (MD = ‒0.04; 95% CI ‒0.29 to 0.22, I2 = 0%) was obtained. A VLCKD encompasses a daily calorie intake of about 600-800 kcal and is low in carbohydrates (< 50 g daily from vegetables) and lipids (only 10 g of olive oil per day).
Implications
The meta-analysis suggests that the DASH diet has an ameliorating effect on serum UA and may be recommended for hyperuricemia states such as gout. Serum UA level following KD remained unchanged.
Uric Acid and Metabolic Diseases
Hyperuricemia is an important risk factor in the development of gout and has strong associations with cardiovascular and metabolic diseases. As uric acid (UA) concentrations are highly dependent on eating habits, weight loss strategies are considered major contributors to decreasing the incidence of hyperuricemia. Dietary approaches, such as the DASH diet, have been shown to profoundly modify hyperuricemia and improve gout symptoms.
Study Methodology
The study was performed in accordance with PRISMA statement 2020 for the Preferred Reporting Items for Systematic Reviews and Meta Analyses. The authors systematically searched online databases including Embase, Web of Science, PubMed, and Scopus for relevant articles until March 2023, using specific Medline keywords related to DASH diet and ketogenic diet. The quality of evidence in each article was methodologically assessed using the Cochrane risk-of-bias tool for randomized trials (RoB-2). Statistical analysis was performed using Stata software.
Study Results
A total of 26,915 studies were obtained with the designed search strategy. After excluding duplicates and irrelevant publications, 10 studies (4 RCTs for DASH and 6 for ketogenic diets) were included in the meta-analysis. The overall risk of bias for DASH diet and KD studies were considered intermediate and high, respectively. The GRADE assessment revealed that the quality of evidence in the meta-analysis of DASH diets was high while the evidence for KD diets was found to be very low.
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DASH Diet Studies
Through the systematic search, 4 relevant RCTs with the DASH diet were identified as eligible to be included in the meta-analysis. A total of 590 participants had been randomized into DASH diet and control arms. DASH diets in all 4 studies consisted of fruits, vegetables, and low-fat dairy foods and reduced consumption of saturated fat, total fat, and cholesterol along with whole grains, poultry, fish, and nuts and restricted red meat, sweets, and sugar-containing beverages.
Ketogenic Diet Studies
The six included trials comprised of 267 participants, 119 of whom were assigned to a VLCKD or control diet, while the remaining individuals were intervened with either LCKD or a comparator diet. All the participants were adults and aged from 18 to 65 years, and their follow-up period varied from 8 to 16 weeks.
Meta-Analysis Findings
The pooled analysis revealed a significant reduction in serum UA following the DASH diet (P < 0.01). KD intervention showed a neutral effect on serum UA. Results of the subgroup analysis of VLCKD studies showed a non-significant reduction in serum UA.
Discussion
The meta-analysis of DASH diet trials showed that despite their different control groups, overall, DASH diet interventions significantly reduced serum UA. The meta-analysis of DASH diet demonstrated a significant reduction in serum UA with a low level of heterogeneity. Foods containing lower glycemic index carbohydrates (e.g., dairy products and some fruits) have reduced UA independent from changes in glucose and insulin levels. Milk-origin proteins, casein and lactalbumin, are purine-free, and their role in lowering serum UA has already been examined in several studies.
Ketogenic Diet and Uric Acid Levels: Potential Mechanisms
The meta-analysis of the available literature has shown that KD has failed to alter UA levels. Most of these studies noted a transient hyperuricemia that is primarily present in the early course of the KD initiation. The hypothesis for the elevated serum UA would be that in KD, when glucose availability drops, other metabolic processes such as ketogenesis rise to compensate for the energy production. Ketone bodies (Beta-hydroxybutyrate and acetoacetate) are products of this increased ketosis. During a ketogenic state, with the accumulation of ketone bodies, the constant gradient of intracellular anions compels urate transporter 1 (URAT1) to reabsorb urate into the cells.
Other Considerations for Managing Gout
Beyond diet, several other factors play a crucial role in managing gout.
Medications
- Flare-Up Medications: People need to take medications, such as nonsteroidal anti-inflammatory drugs, within 24 hours of a flare-up onset.
- Anti-Urate Medications: Some people with gout may need to take medications that lower the amount of uric acid in the blood.
Lifestyle Modifications
- Reducing Alcohol Consumption: Alcohol, especially beer, is known to increase uric acid levels.
- Maintaining a Moderate Weight: Weight management is crucial for overall health and can help reduce gout flare-ups.
- Staying Well-Hydrated: Drinking plenty of water helps the kidneys flush out uric acid.
Addressing Common Misconceptions
- Protein is the Enemy: While high-purine foods should be limited, moderate protein intake is generally acceptable. In a large study that followed 47,150 people over 12 years, researchers found the opposite: dairy consumption was inversely correlated with gout risk.
- Fructose is a Major Culprit: Sugar is a much more likely contributor to gout than protein. The most common source of fructose in the modern diet is high-fructose corn syrup.
- Keto as a Preventative Measure: The available research suggests that the keto diet may help target the source of the inflammation to prevent acute symptoms of gout, but it hasn’t been shown to prevent the condition.
The Importance of Medical Guidance
It’s important to remember that the right kind of diet can play an important role in managing gout, as long as it’s used with - and not in place of - prescription drugs. “I always encourage strict compliance with our gout medications, but try very hard to emphasize the importance of diet to treat the patient as a whole - not just their arthritis,” says Dr.