Nightshade intolerance is one of the less well-known food sensitivities, but for those affected, it can be genuinely disruptive. Nightshades are a family of plants that include some of the UK's most commonly eaten vegetables — tomatoes, potatoes, peppers, and aubergines. While these foods are nutritious for most people, a subset of individuals find that they trigger inflammation, joint pain, digestive problems, or skin reactions. The challenge is that symptoms are often delayed, making the connection hard to spot without deliberate tracking.
Nightshades belong to the Solanaceae plant family, which includes over 2,000 species. The edible varieties are a staple of the UK diet, making them difficult to avoid without awareness of exactly which foods are included.
| Nightshade Food | Common UK Uses | Glycoalkaloid Content |
|---|---|---|
| Tomatoes | Salads, pasta sauces, ketchup, pizza, soups, tinned tomatoes | Tomatine (moderate) |
| White potatoes | Chips, mash, jacket potatoes, crisps, roast dinners | Solanine (moderate, higher when green or sprouted) |
| Bell peppers | Stir-fries, salads, stuffed peppers, fajitas | Capsaicin, solanine (low to moderate) |
| Chilli peppers | Curries, sauces, chilli con carne, hot sauces | Capsaicin (high) |
| Aubergine (eggplant) | Moussaka, ratatouille, baba ganoush, curries | Solanine (moderate) |
| Paprika | Spice blends, seasoned meats, crisps, hummus | Capsaicin (varies) |
| Cayenne pepper | Hot sauces, spice blends, seasoning | Capsaicin (high) |
| Goji berries | Health snacks, smoothies, trail mixes | Low |
Sweet potatoes, black pepper, blueberries, and mushrooms are not nightshades — despite sometimes being mistakenly included. These are safe to eat on a nightshade-free elimination diet.
Nightshade sensitivity symptoms can affect multiple body systems and are often delayed by hours or even a day, which makes identification particularly challenging. Here are the most commonly reported symptoms.
While anyone can develop a nightshade sensitivity, certain groups appear to be more likely to experience adverse reactions.
Some research and clinical observations suggest that glycoalkaloids may increase intestinal permeability (sometimes called "leaky gut") in susceptible individuals. This is of particular interest to people with autoimmune conditions such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease. Some autoimmune protocols (such as the AIP diet) recommend eliminating nightshades as part of an anti-inflammatory approach.
If you already have IBS, acid reflux, or other digestive conditions, you may be more likely to react to nightshades — particularly tomatoes (which are acidic) and chilli peppers (which contain capsaicin, a known gut irritant).
Some dermatologists report that patients with eczema or psoriasis occasionally experience improvement when nightshades are removed from their diet. This is anecdotal rather than conclusively proven, but it is worth investigating if you have persistent skin issues that do not respond to other dietary changes.
Nightshade intolerance is not as extensively studied as conditions like coeliac disease or lactose intolerance. While some peer-reviewed research supports the role of glycoalkaloids in affecting gut permeability and inflammation, much of the evidence is preliminary or based on clinical observation. This does not mean it is not real — it means that an elimination approach with careful tracking is currently the best way to determine if nightshades affect you personally.
Because there is no blood test or skin prick test for nightshade intolerance, a structured elimination and reintroduction approach is the gold standard for identification.
Before eliminating anything, track your current diet and symptoms for 1-2 weeks. Note which nightshade foods you eat, how much, and record any joint pain, digestive issues, or skin problems. Rate symptom severity on a simple 1-10 scale to measure changes objectively.
Remove all nightshade foods from your diet for at least 3 weeks (4 weeks is better, especially for joint-related symptoms which can take longer to resolve). This means avoiding:
Continue tracking your symptoms throughout this phase.
Reintroduce one nightshade food at a time, eating a moderate portion and then waiting 3 days before trying the next. This spacing accounts for delayed reactions.
Record symptoms carefully after each reintroduction. NutraSafe can help you track this process systematically, logging meals and symptoms in one place so patterns become clear.
Removing nightshades does not mean eating bland food. Here are practical swaps for common UK meals.
If you suspect nightshade intolerance, consider discussing it with your GP or a registered dietitian before starting an elimination diet. They can help rule out other conditions (such as inflammatory bowel disease or rheumatoid arthritis) and ensure your diet remains nutritionally balanced. Nightshade vegetables are rich in vitamins C and A, potassium, and fibre — so finding adequate replacements matters.
NutraSafe helps you log meals, scan ingredients for hidden nightshades, and track symptoms — making your elimination and reintroduction process structured and effective.
Download Free on the App StoreNightshades are plants from the Solanaceae family. The most common edible nightshades in the UK diet are tomatoes, white potatoes, peppers (bell peppers, chilli peppers), aubergines (eggplant), and paprika. They contain natural compounds called glycoalkaloids (including solanine and tomatine) which some people may be sensitive to.
Common nightshade intolerance symptoms include joint pain and stiffness, digestive issues (bloating, stomach pain, diarrhoea), skin problems (eczema flare-ups, rashes, itching), headaches, and general inflammation. Symptoms are often delayed, appearing hours to a day after consumption, which makes them difficult to identify without systematic tracking.
Nightshade intolerance is not as well-established in scientific literature as lactose intolerance or coeliac disease. However, nightshades do contain glycoalkaloids which can affect gut permeability and inflammation in some individuals. Some rheumatologists and gastroenterologists acknowledge that a subset of patients report symptom improvement when nightshades are removed. More research is needed.
There is no standard medical test for nightshade intolerance. The recommended approach is an elimination diet: remove all nightshade foods for 2-4 weeks while tracking your symptoms, then reintroduce them one at a time. If symptoms improve during elimination and return upon reintroduction, this strongly suggests a nightshade sensitivity. Ideally, work with a registered dietitian.
Good UK alternatives include sweet potatoes (not true nightshades) instead of white potatoes, beetroot and carrots for colour and nutrition, courgettes and mushrooms as versatile vegetable swaps, black pepper and turmeric instead of paprika and chilli, and cauliflower or parsnip mash instead of mashed potato.
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Last updated: February 2026