Psoriasis is an autoimmune disease that’s marked by red, itchy, scaly patches that usually show up on your elbows, knees, scalp, and lower back. It affects over 7.5 million adults in the United States today.1 However, psoriasis isn’t just a skin problem — it’s a systemic inflammatory condition that could lead to joint damage, chronic fatigue, and metabolic disease.
Researchers recently discovered a powerful independent risk factor for developing psoriasis among women — abdominal fat. In fact, they found that belly fat specifically is more predictive of psoriasis than overall body fat. This proves that the fat around your waist is a warning sign that your immune system is on high alert, and the inflammatory cascade it triggers could be the hidden driver behind this skin condition.
Abdominal Fat — A More Powerful Predictor of Psoriasis Than Weight Alone
A recent investigation published in the Journal of Investigative Dermatology set out to determine whether the specific location of body fat, rather than overall fat mass, influences the risk of developing psoriasis.2 Conducted by researchers from King’s College London, the study used data from the UK Biobank, one of the world’s most robust population-based datasets, to assess how body fat is associated with this skin condition.3
• Determining the study participants — Data from over 330,000 individuals, including more than 9,000 diagnosed cases of psoriasis were analyzed. Importantly, the researchers assessed 25 different fat distribution measures, using both traditional methods and advanced imaging, to identify which were most strongly linked to the disease.
• All participants were of White British ancestry to control for genetic variation — Within this population, the researchers found that abdominal fat — often referred to as visceral, central, or belly fat — was significantly more predictive of psoriasis risk than total body fat.
• Women were particularly vulnerable — Based on their findings, visceral fat volume had a much higher odds ratio in females than in males — 1.35 vs. 1.13 respectively — indicating that fat stored around the organs in the abdomen may be more inflammatory or more biologically active in women.
• The risk remained consistent even after adjusting other factors — These include body mass index (BMI), family history, and other conventional risk factors, establishing abdominal fat as a strong independent contributor to psoriasis.
• Even if you’re not genetically predisposed to psoriasis, belly fat still increases your risk — The researchers found that individuals who did not carry the HLA-C06:02 gene variant — a known risk factor for psoriasis — were more strongly affected by fat-related risk. The waist-to-hip ratio had a significantly greater impact in HLA-C06:02-negative individuals.
This means that for people without a strong inherited risk, lifestyle factors like fat distribution play an even bigger role in determining their psoriasis risk.
This study challenges long-held assumptions about how psoriasis develops. Waist circumference, once dismissed as a cosmetic measurement, now emerges as a critical biomarker for systemic inflammation and immune risk.
If you’re managing psoriasis or concerned about its onset, focusing on reducing central fat could offer a more targeted and effective strategy than simply aiming for a lower number on the scale. According to Prof. Catherine H. Smith, senior author of the study:4
“As rates of obesity continue to rise globally, understanding how different patterns of body fat influence chronic inflammatory conditions such as psoriasis is important.
Our findings suggest that central body fat contributes to psoriasis risk irrespective of genetic predisposition and reinforces the importance of measuring waist circumference and pro-active healthy weight strategies in psoriasis care.”
The More Weight You Gain, the Greater Your Risk of Joint Disease
When psoriasis is left unchecked, it can progress into psoriatic arthritis, which causes swelling, pain, and stiffness that mimic rheumatoid arthritis and permanently damages your joints. So what does fat have to do with this? It turns out, carrying excess weight, particularly around the abdomen, also increases psoriatic arthritis risk in women.
A long-term prospective study published in the Annals of the Rheumatic Diseases examined the link between body composition and the risk of developing psoriatic arthritis among women. Using data from the Nurses’ Health Study II, researchers tracked 89,049 U.S. female participants over a 14-year period to determine whether excess weight and fat distribution contributed to the onset of psoriatic arthritis.5
• Participants were free of psoriatic arthritis at the start of the study — They were then followed for 14 years, with their data collected twice a year using mailed questionnaires. The researchers gathered information such as their BMI, waist and hip circumference, weight changes since they were 18 years old, lifestyle factors (such as cigarette use or alcohol intake), and medical diagnoses, including psoriasis and psoriatic arthritis.
• Over time, 146 incident cases of psoriatic arthritis were confirmed — When stratified by BMI, the findings were conclusive — women with a BMI of 35 or higher had over six times the risk of developing psoriatic arthritis compared to women with a BMI under 25.
• The study further evaluated the role of fat distribution, specifically abdominal fat — Looking at the participants’ waist and hip measurements, the researchers found that central adiposity — excess fat stored around the abdomen — was independently associated with increased psoriatic arthritis risk. These associations persisted even after adjusting for different factors.
• The temporal aspect of weight gain was another critical factor — Women who were already overweight at age 18 exhibited an elevated risk, but those who experienced significant weight gain in subsequent decades faced substantially greater odds of developing psoriatic arthritis. This suggests that disease risk intensifies not solely from early-life weight status but through prolonged exposure to excess weight and chronic metabolic strain.
This study offers a rigorous, longitudinal perspective on how body composition affects psoriatic arthritis risk. It affirms that excess abdominal fat is more than a cosmetic concern, but a measurable, inflammatory burden that significantly increases your risk of chronic autoimmune disease. Importantly, it identifies abdominal fat and cumulative weight gain as modifiable risk factors, meaning there’s a clear opportunity to prevent and manage this disease.
Vitamin D Deficiency — Another Contributing Factor to Psoriasis
While you may be familiar with vitamin D for its role in bone health and calcium regulation, there’s now research showing that its benefits extend to your skin health. Vitamin D helps to regulate the proliferation and differentiation of keratinocytes — the cells responsible for forming your skin’s outer layer. In fact, this nutrient plays a role in immune modulation and skin health, by reducing inflammation and supporting your skin barrier.
• Despite its availability, vitamin D deficiency is a common problem today — Aside from a handful of foods like fatty fish and supplements, getting vitamin D means exposing your skin to sunlight. This is important for those living in northern latitudes or have darker skin that reduces vitamin D synthesis. For people with psoriasis, vitamin D deficiency may not just be a consequence of avoiding sun exposure but could also be linked to the disease’s underlying mechanisms.
• Low levels of vitamin D were associated with psoriasis — A systematic review and meta-analysis of 23 studies revealed that individuals with psoriasis have significantly lower serum levels of vitamin D compared to healthy controls. On average, the vitamin D levels of psoriasis patients were 6.26 ng/mL lower than those of individuals without the condition.6
• People with psoriasis also have elevated levels of parathyroid hormone (PTH) — This hormone is a marker often associated with low vitamin D. High PTH levels could reflect the body’s effort to maintain calcium balance despite vitamin D deficiency. Some researchers suggest that PTH might even play a role in psoriasis pathogenesis by influencing immune activity, particularly the proliferation of proinflammatory T-helper 17 (Th17) cells.
• The lower your vitamin D levels, the worse your psoriasis is — A separate study, presented at the American Society for Nutrition 2023 meeting, looked at 500 psoriasis cases and found that patients with the smallest areas of skin affected by the disease had the highest average levels of vitamin D, while those with the most extensive lesions showed the lowest levels.7
• Mindful sun exposure is the best way to support your vitamin D levels — It also allows you to gain other health benefits tied to sunlight and spending time outdoors, such as reduced cancer risk and improved longevity. Learn more about the benefits of sun exposure in “Beyond Vitamin D Production — How Sensible Sun Exposure Supports Overall Health.”
• A reminder about sun exposure — It’s important that you avoid direct sunlight during peak hours (10 a.m. to 4 p.m.) until you’ve reduced your seed oil consumption for at least two to six months. This is because the linoleic acid (LA) in these oils accumulates in your skin, and when it interacts with the sun’s UV rays, it triggers inflammation and DNA damage.
My Mercola Health Coach app will officially be released this year, and one of its main features is the Seed Oil Sleuth — It calculates your vegetable oil intake to the tenth of a gram, and is a helpful way to keep track of your seed oil consumption, to ensure that you’re slowly but surely reducing your intake.
• A faster way to purge LA from your skin — I recently discovered that consuming pentadecanoic acid or C15:0, a special fat found in raw grass fed milk, helps purge LA embedded in your skin faster. Increasing your intake of C15:0 to 2 grams per day causes your keratinocytes to incorporate it instead of LA within a single skin-cycle (around four weeks).
This means that if you continue drinking raw milk, the LA on your skin should go down by 25% to 30% within three to four months. When you keep it up for 12 to 18 months, the LA in your adipose tissue will decrease by 80%, instead of two to three years by following a low-LA diet alone. After doing this, whatever remaining ultraviolet risks on your skin come from direct DNA damage and can’t be fixed by your diet.
Reduce the Root Causes Driving Psoriasis and Joint Disease
If you are dealing with psoriasis — or concerned about your risk of developing it or its related joint complications — you must concentrate on reducing your abdominal fat. It’s not just a cosmetic issue; it’s a biological one, as it plays an active role in driving inflammation. Addressing this specific type of fat gives you the most direct path to improving immune balance and reducing disease progression. Here are practical strategies to help address this root cause and support long-term health:
1. Prioritize fat loss if you already have psoriasis — If you are currently managing psoriasis, central fat reduction should be one of your primary health goals. Begin by removing sugar-sweetened beverages, minimizing processed foods, and centering your meals around nutrient-dense whole foods. Combine this with daily movement to gradually reduce abdominal fat and ease the systemic inflammatory burden on your body.
2. Monitor your waist-to-hip ratio — Rather than relying solely on weight or BMI, begin regularly measuring your waist-to-hip ratio. For women, a ratio above 0.85 is associated with increased inflammatory risk. This measurement more accurately reflects fat distribution, so track this number monthly, so you’ll be able to see your progress more accurately.
3. Incorporate moderate-intensity exercises to improve fat metabolism — A consistent walking routine — particularly for 10 to 15 minutes after meals — will significantly improve your body’s ability to manage blood glucose and metabolize fat. If you’ve experienced gradual weight gain over the years, this is a simple yet effective intervention to begin reversing that trend.
4. Replace seed oils with healthy fats — The LA in soybean, corn, canola, and safflower oils contribute to systemic inflammation,8,9 promote fat accumulation, and, as mentioned above, worsen psoriasis by accumulating in your skin and causing damage. Replace these seed oils with anti-inflammatory alternatives such as grass fed butter, ghee, beef tallow, or coconut oil.
5. Adopt a consistent eating window to support hormonal balance — Irregular or late-night snacking leads to chronic elevation of insulin and promotes abdominal fat storage. A simple but effective approach is time-restricted eating (TRE), where you consume all meals within an eight-hour window, preferably during daylight hours. This pattern supports better insulin sensitivity, reduces fat accumulation, and enhances overall metabolic function.
Consistently applying these strategies will help you take control of one of the most important drivers behind psoriasis and psoriatic arthritis. However, if you’re already diagnosed with this condition, don’t worry — although it’s not curable, there are ways to manage it and prevent flareups. I recommend reading “Eczema and Psoriasis — Different Causes, Similar Symptoms” for a list of natural remedies to control this condition.
Frequently Asked Questions (FAQs) About Abdominal Fat and Psoriasis
Q: How is abdominal fat connected to psoriasis?
A: Abdominal fat, especially visceral fat stored around your organs, triggers inflammation that can activate your immune system in harmful ways. Studies show it’s a stronger predictor of psoriasis risk than overall weight or BMI.
Q: Why are women more affected by this connection than men?
A: Research has found that abdominal fat appears to be more biologically active in women, leading to a stronger inflammatory response. This increases their susceptibility to psoriasis and related joint diseases like psoriatic arthritis.
Q: Can you still develop psoriasis from belly fat even without a genetic predisposition?
A: Yes. Even women without genetic markers linked to psoriasis are at higher risk if they carry excess belly fat. This proves that lifestyle-related fat distribution plays a central role in disease development.
Q: What’s the link between psoriasis and joint damage?
A: If psoriasis isn’t addressed, it can lead to psoriatic arthritis — a painful condition that damages your joints over time. Abdominal fat further increases this risk, especially in women who gain weight over several decades.
Q: What are the most effective ways to lower your risk?
A: Focus on reducing central fat through daily walking and cutting out seed oils, replacing them with healthier fats. An intermittent fasting regimen like TRE can also be helpful. Just make sure you’re getting enough carbs (ideally around 250 grams per day). Tracking your waist-to-hip ratio regularly to monitor your progress.