Anti-Nutrients: understanding their role, assessing concerns, and supporting optimal nutrition

At FROM WITHIN, I frequently encounter clients who are passionate about whole food nutrition but feel uncertain when they hear terms like "anti-nutrients." Many wonder if these compounds in everyday plant foods, such as spinach, beans, nuts or grains, are quietly undermining their health, contributing to fatigue, digestive discomfort, or nutrient shortfalls. These questions often arise alongside broader goals of enhancing energy, gut health, or overall vitality. As a certified practising nutritionist (CPN), I approach this topic with a balanced, evidence-based lens: anti-nutrients are natural elements of plant-based foods that can influence nutrient absorption, but their effects are often manageable and context-dependent. This article explores what anti-nutrients are, evaluates whether they warrant concern based on current research, and outlines practical, personalised strategies to minimise their impact, helping you nourish your body from within, confidently and holistically.

What are anti-nutrients?

Anti-nutrients are naturally occurring compounds in plant foods that can bind to or interfere with the absorption of essential nutrients during digestion. They evolved as protective mechanisms for plants, deterring pests and aiding survival in challenging environments. While the term "anti-nutrient" implies opposition to health, these compounds are integral to many nutrient-dense foods and, in moderation, may even offer benefits when part of a varied diet (Petroski & Minich, 2020).

Common anti-nutrients include:

Phytates (phytic acid): Found in grains, legumes, nuts, and seeds (e.g., lentils, almonds, and quinoa). They bind minerals such as iron, zinc, and calcium, potentially reducing their bioavailability (Petroski & Minich, 2020).

Oxalates: Present in leafy greens such as spinach and kale, as well as beetroot and rhubarb. These can form insoluble complexes with calcium, limiting its absorption and, in susceptible individuals, may contribute to kidney stone formation (Mitchell et al., 2019).

Lectins: Occur in legumes, grains, and nightshades such as tomatoes and potatoes. They may bind to gut lining cells, potentially causing irritation, if foods are not prepared properly (Vojdani, 2015).

Tannins: Abundant in tea, coffee, wine, and some fruits (e.g., unripe bananas). They can inhibit iron absorption and create a bitter taste (Samtiya et al., 2020).

Goitrogens: Found in cruciferous vegetables (e.g., broccoli and cabbage). These can interfere with iodine uptake and thyroid function, though effects are typically mild and reversible (Petroski & Minich, 2020).

At FROM WITHIN, we emphasise that these compounds often coexist with valuable nutrients. For example, phytates have antioxidant properties that may support metabolic health (Graf et al., 2022). Our bodies are adapted to process them in balanced amounts, particularly when diets are diverse and foods are prepared thoughtfully. However, when intake is high or preparation is minimal (e.g., raw, un-soaked grains), they may contribute to subtle imbalances over time.

Should you be concerned about anti-nutrients?

The degree of concern around anti-nutrients depends on individual factors, including overall diet quality, health status, and nutrient needs. Recent evidence suggests that while they can affect absorption, the risks are often overstated for most people, and blanket avoidance is rarely necessary (Petroski & Minich, 2020).

On the potential downside, anti-nutrients may reduce nutrient bioavailability. For example, phytates can lower iron absorption by 50–70% in plant-based diets, which could exacerbate deficiencies in at-risk individuals such as vegetarians or those with anaemia (Gibson et al., 2018). Oxalates have been linked to decreased calcium uptake, potentially impacting bone health in older adults or those prone to osteoporosis (Mitchell et al., 2019). Lectins, if consumed in large amounts without cooking, may irritate the gut lining, contributing to digestive symptoms in sensitive individuals (Vojdani, 2015). Tannins and goitrogens can similarly affect iron and thyroid function, respectively, though effects are dose-dependent and often minimal in cooked forms (Samtiya et al., 2020; Petroski & Minich, 2020).

That said, a 2020 narrative review challenges the "anti" label, noting that many of these compounds provide health benefits. For instance, tannins' play a protective role in cardiovascular health through their antioxidant activity (Samtiya et al., 2020), while goitrogens in cruciferous vegetables, when prepared appropriately, support detoxification and anti-inflammatory pathways (Petroski & Minich, 2020). In well-nourished populations with varied diets, the net impact is typically low, as our digestive systems compensate effectively (Graf et al., 2022).

Certain groups may benefit from greater awareness such as pregnant individuals, vegans, those with gastrointestinal conditions (e.g., IBS), thyroid issues, or known deficiencies. A 2022 study found that high-oxalate diets increased kidney stone risk in predisposed people, but this was mitigated by hydration and balanced intake (Graf et al., 2022). At FROM WITHIN, I've observed that clients experiencing symptoms such as persistent fatigue or bloating, often see improvements through targeted adjustments rather than elimination. If concerns arise, I recommend tracking symptoms and considering basic labs (e.g., iron or zinc levels) in collaboration with their healthcare team to rule out deficiencies (Gibson et al., 2018). Overall, evidence points to anti-nutrients as manageable aspects of plant-rich eating, not inherent threats, when approached with informed strategies (Petroski & Minich, 2020).

Strategies to minimise the effects of anti-nutrients

The good news is that traditional preparation methods, rooted in cultural wisdom and supported by science, can significantly reduce anti-nutrient levels, enhancing digestibility and nutrient access without compromising the benefits of whole foods. At FROM WITHIN, we tailor these to your lifestyle, symptoms, and preferences, ensuring changes feel sustainable and supportive.

Soaking and sprouting: These activate enzymes that break down phytates and lectins. Soaking legumes or nuts for 8–12 hours can reduce phytic acid by 30–50%, while sprouting grains like quinoa may decrease it by up to 90% (Shi et al., 2018; Petroski & Minich, 2020). This is particularly helpful for plant-based eaters; we might start with simple overnight soaks in your meal prep routine.

Fermentation: Beneficial microbes in fermented foods (e.g., sauerkraut or miso) degrade anti-nutrients naturally. Research shows fermented legumes have lower lectin and phytate content, improving gut tolerance and mineral absorption (Samtiya et al., 2020). If gut sensitivity is an issue, we introduce these gradually to build microbiome resilience.

Cooking and heat treatment: Blanching, boiling, steaming, or pressure cooking neutralises many compounds. For instance, cooking beans reduces lectins by 99%, and heat diminishes goitrogens in vegetables (Shi et al., 2018; Mitchell et al., 2019). We focus on methods that preserve nutrients, such as gentle steaming or blanching, to maintain overall food quality.

Strategic food pairing and diversity: Pair anti-nutrient-rich foods with enhancers, for example, vitamin C can boost iron absorption by 200–300% despite phytates (Gibson et al., 2018). Combining oxalate sources with calcium (e.g., dairy or fortified options) helps bind them in the gut (Graf et al., 2022). A diverse diet prevents overexposure, incorporating proteins and varied plants for balanced intake (Petroski & Minich, 2020).

Navigating anti-nutrients amid the wealth of online information can feel overwhelming, especially if your experiencing symptoms. At FROM WITHIN, we create personalised, evidence-based nutrition plans that integrate your unique health picture, we consider your diet, lifestyle, and any testing, to ensure nutrition supports rather than hinders you. If you're curious whether anti-nutrients play a role in your wellbeing and want a clear, compassionate path forward, book a consult here and together, we'll build strategies that help you thrive from within.

Recipe:

Buckwheat Power Bowl that’s designed to minimise anti-nutrients through soaking, gentle cooking, and smart pairings. Buckwheat base, protein-packed chickpeas, roasted veggies, and a lemon-tahini dressing come together for a balanced, gut-friendly meal.

Buckwheat Power Bowl with Crispy Chickpeas and Roasted Veg

Servings: 4 Prep + cook time: ~60 minutes (hands-on time, plus soaking)

Why this works for anti-nutrient minimisation

• Uses soaked and well-cooked components to reduce antinutrients e.g., phytates.

• Buckwheat is gentle on the digestive system and a nutrient-dense base; chickpeas provide plant protein after soaking

• Includes vitamin C-rich dressing and veggies to boost iron absorption and gut health.

• All parts are cooked with gentle methods and balanced with healthy fats and fibre.

 Ingredients

For the bowl

o    1 cup buckwheat groats, soaked 6–8 hours, drained

o    1 1/2 cups cooked chickpeas, soaked 8–12 hours, then simmered until tender (or 2 cups tinned organic (BPA free) chickpeas, drained and rinsed)

o    2 cups sweet potato cubes

o    2 cups broccoli florets or broccolini

o    1 red capsicum, sliced

o    2 cups kale, chopped (or use Kale & Spinach salad mix)

o    2 tablespoons extra virgin olive oil (EVOO), divided

o    1 teaspoon ground cumin

o    1/2 teaspoon paprika

o    Salt and black pepper, to taste

 Tahini lemon dressing

o    3 tablespoons tahini

o    2 tablespoons lemon juice

o    1 small garlic clove, minced

o    2–4 tablespoons water (to reach pourable consistency)

o    1 tablespoon EVOO

o    Pinch of salt

Toppings (optional)

o    2 tablespoons chopped parsley or coriander

o    1/4 cup pumpkin seeds and/or sunflower seeds

o    Lemon wedges for serving

Method

1. Soak and prep

• Buckwheat: soak 6–8 hours, drain and rinse well.

• Chickpeas: soak 8–12 hours, drain and rinse; simmer in fresh water until tender (about 25–35 minutes). If using canned, skip soaking and simply rinse well.

2. Cook buckwheat

• In a pot, add buckwheat with 2 cups water and a pinch of salt. Bring to a simmer, cover, and cook 12–15 minutes until tender. Fluff and set aside.

3. Roast vegetables

• Preheat oven to 200°C (400°F).

• Toss sweet potato, broccoli, and pepper with 1 tablespoon olive oil, cumin, paprika, salt, and pepper.

• Roast 20–25 minutes, until tender and caramelised. Add kale in the last 3–5 minutes to wilt.

4. Dress and assemble

• Whisk dressing ingredients in a bowl or use a jar to shake: tahini, lemon juice, garlic, olive oil, water), and salt. Adjust thickness with more water.

• In bowls, layer buckwheat as base, add chickpeas, roasted veggies, and kale.

• Drizzle with dressing, top with parsley and seeds, and serve with a lemon wedge.

References
Gibson, R. S., Raboy, V., & King, J. C. (2018). Implications of phytate in plant-based foods for iron and zinc bioavailability, setting dietary requirements, and formulating programs and policies. Nutrition Reviews, 76(10), 793–804. https://doi.org/10.1093/nutrit/nuy028

Graf, B. L., Rojas-Silva, P., Rojo, L. E., Delatorre-Herrera, J., Baldeón, M. E., & Raskin, I. (2022). Innovations in health value and functional food development of quinoa (Chenopodium quinoa Willd.). Comprehensive Reviews in Food Science and Food Safety, 21(2), 1385–1412. https://doi.org/10.1111/1541-4337.12915

Mitchell, T., Kumar, P., Reddy, T., Wood, K. D., Knight, J., Assimos, D. G., & Holmes, R. P. (2019). Dietary oxalate and kidney stone formation. American Journal of Physiology-Renal Physiology, 316(3), F409–F413. https://doi.org/10.1152/ajprenal.00373.2018

Petroski, W., & Minich, D. M. (2020). Is there such thing as “anti-nutrients”? A narrative review of perceived problematic plant compounds. Nutrients, 12(9), 2559. https://doi.org/10.3390/nu12092559

Samtiya, M., Aluko, R. E., & Dhewa, T. (2020). Plant food anti-nutritional factors and their reduction strategies: An overview. Food Production, Processing and Nutrition, 2(1), 6. https://doi.org/10.1186/s43014-020-0020-5

Shi, L., Arntfield, S. D., & Nickerson, M. (2018). Changes in levels of enzyme inhibitors during soaking and cooking for pulses available in Canada. Journal of Food Science and Technology, 55(1), 309–320. https://doi.org/10.1007/s13197-017-2942-3

Vojdani, A. (2015). Lectins, agglutinins, and their roles in autoimmune reactivities. Alternative Therapies in Health and Medicine, 21(Suppl 1), 46–51.