Understanding FODMAPs and Nuts
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are types of short-chain carbohydrates that can be poorly absorbed in the small intestine, leading to digestive issues such as bloating, gas, and abdominal pain in sensitive individuals, particularly those with Irritable Bowel Syndrome (IBS). Nuts are a fantastic source of healthy fats, protein, fiber, and essential nutrients, but their FODMAP content can vary significantly, with some varieties being gut-friendly in small quantities while others should be avoided. The key to including nuts in a low FODMAP diet is understanding which ones are safe and, most importantly, respecting the recommended portion sizes established by institutions like Monash University.
Safe Low FODMAP Nuts and Their Serving Sizes
For those following a low FODMAP diet, several nuts can be enjoyed without worry, provided you adhere to the specified portion limits. These delicious and nutritious options include:
Brazil Nuts
These large, creamy nuts are an excellent source of selenium, a crucial mineral for thyroid and immune function. The low FODMAP serving size is 10 nuts (approximately 40g), but it's often recommended to stick to just one or two per day to avoid excessive selenium intake. They can be eaten raw, chopped into salads, or blended into smoothies.
Chestnuts
Both boiled and roasted chestnuts are considered low FODMAP. The Monash University guidelines state that a serving size of 10 roasted chestnuts is safe. They are rich in vitamin C and minerals, making them a nutritious seasonal treat.
Macadamia Nuts
With their rich, buttery flavour, macadamia nuts are very low in FODMAPs and can be enjoyed in a generous serving of up to 15-20 nuts (40g). They are high in heart-healthy monounsaturated fats, which may help lower cholesterol.
Peanuts
Technically a legume but nutritionally similar to tree nuts, peanuts are a safe and budget-friendly option. The recommended serving size is 32 peanuts (28g). Be sure to choose plain, unsalted varieties and check labels on peanut butter to avoid high FODMAP additives like high-fructose corn syrup.
Pecans
Pecans are a fantastic source of antioxidants, thiamine, and magnesium. A low FODMAP serving is 10 pecan halves (30g). They add a sweet, buttery crunch to salads, oatmeal, or baked goods.
Pine Nuts
Often used in pesto, these small, delicate nuts have a low FODMAP serving size of one tablespoon. Larger servings contain high amounts of fructans, so careful portioning is essential.
Walnuts
Walnuts are packed with anti-inflammatory omega-3 fatty acids, beneficial for brain and heart health. A safe low FODMAP serving consists of 10 walnut halves (30g).
Nuts with Restricted Portions on a Low FODMAP Diet
Some nuts are only considered low FODMAP in very small, carefully measured quantities due to their galacto-oligosaccharides (GOS) content.
Almonds
Almonds are a versatile and nutrient-dense nut, but their FODMAP content increases with portion size. A low FODMAP serving is limited to 10 nuts. Larger servings (20 almonds or more) become high in GOS. Almond butter is also limited to one tablespoon per serving.
Hazelnuts
Like almonds, hazelnuts are only low FODMAP in small quantities. A safe serving size is 10 nuts or less, as larger portions become high in GOS.
Nuts to Avoid on a Low FODMAP Diet
Certain nuts are high in FODMAPs even in small amounts and should be avoided during the elimination phase of the diet to prevent triggering symptoms.
- Cashews: These are high in GOS and fructans, making them unsuitable for the low FODMAP diet. Note that some activated cashews (soaked and dehydrated) may be tolerated in small servings, but caution is advised.
- Pistachios: Pistachios are high in GOS and should be avoided.
Low FODMAP Nuts: Portion Size Comparison Table
| Nut Type | Safe Low FODMAP Serving Size | Primary FODMAP in Larger Servings |
|---|---|---|
| Brazil Nuts | 10 nuts (limit due to selenium) | - |
| Chestnuts (Roasted) | 10 chestnuts | - |
| Macadamia Nuts | 15–20 nuts (40g) | - |
| Peanuts | 32 nuts (28g) | Fat can trigger symptoms in large amounts |
| Pecans | 10 halves (30g) | - |
| Pine Nuts | 1 tablespoon | Fructans |
| Walnuts | 10 halves (30g) | - |
| Almonds | 10 nuts | GOS |
| Hazelnuts | 10 nuts | GOS |
| Cashews | Not low FODMAP | GOS and Fructans |
| Pistachios | Not low FODMAP | GOS and Fructans |
Tips for Incorporating Low FODMAP Nuts into Your Diet
Successfully adding nuts to your low FODMAP meal plan is simple with these strategies:
- Snack Smart: Portion out a handful of safe nuts like macadamias or pecans into small containers for a quick, grab-and-go snack.
- Enhance Breakfast: Sprinkle chopped walnuts or pecans over lactose-free yogurt or oatmeal for added crunch and nutrients.
- Boost Salads: Add a tablespoon of toasted pine nuts or a few pecan halves to salads for extra flavour and texture.
- Make Healthy Sauces: Create a low FODMAP pesto using pine nuts and garlic-infused olive oil, as onion and garlic are high FODMAP.
- Check Labels: Always scrutinize the ingredients list on packaged nut products, including butters and mixes, to ensure no high FODMAP additives like honey, garlic powder, or inulin have been included.
Conclusion
Navigating which nuts can you eat on a low fodmap diet is a matter of knowing your portion sizes and distinguishing between varieties. You can safely enjoy a wide range of delicious and nutritious nuts, including peanuts, macadamias, pecans, and walnuts, by keeping track of quantities. Be cautious with almonds and hazelnuts, and steer clear of cashews and pistachios during the elimination phase. By following these guidelines, you can reap the significant health benefits of nuts without triggering digestive distress. For the most accurate and up-to-date information, consulting with a registered dietitian or using the Monash University FODMAP Diet App is recommended.
