Antinutrients to Avoid for Stronger Bones: Lectins, Phytates, and Oxalates‍

Why Antinutrients Matter for Bone Health

Certain natural compounds in plants, called antinutrients, can bind minerals or affect digestion, which may interfere with nutrient absorption if eaten in excess or without proper preparation.

Today, we’ll explore three key groups that can influence bone and mineral metabolism: lectins, phytates, and oxalates.

Lectins: Plant Defense Proteins

Lectins are carbohydrate-binding proteins found in many plants, particularly legumes and grains. They serve as part of the plant’s natural defense system and can bind to sugars on cell surfaces in the gut.

When consumed in large amounts or undercooked, lectins may:

• Bind to nutrients, reducing absorption.
  
  
• Cause mild digestive irritation in sensitive individuals.
  
  

Foods containing lectins include:

• Red kidney beans (especially raw or undercooked) can cause toxicity. 
• Soybeans
  
  
• Wheat
  
  
• Peanuts
  
  
• Tomatoes and potatoes (contain much lower, generally safe amounts)
  
  

Cooking and soaking greatly reduce lectins; boiling beans for at least 10 minutes destroys most active lectins. Well-cooked legumes, grains, and vegetables are safe for most people.

“Sometimes you can feel lectin sensitivity, and sometimes you can’t. That’s why I encourage patients to experiment—track what you eat, how it’s prepared, and how you feel afterward.” – Dr. Doug Lucas

Current evidence shows that properly prepared lectin-containing foods are safe for most people and provide valuable nutrients. True lectin intolerance is rare, and elimination should only be considered if symptoms persist.

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Phytates (Phytic Acid): Mineral Binders, Not Always Villains

Phytates, or phytic acid, are storage forms of phosphorus in plants. They can bind minerals like calcium, iron, and zinc, reducing absorption when diets are already low in those minerals.

However, context matters:

• In mixed, nutrient-dense diets, phytates have antioxidant properties and may even protect against some chronic diseases.
  
  
• Problems arise mainly in low-mineral, high-phytate diets (common where grains and legumes are dietary staples without fortification).
  
  

Foods rich in phytates:

• Whole grains (wheat, rice, oats)
  
  
• Legumes (beans, lentils, peanuts)
  
  
• Nuts (almonds, walnuts, pine nuts)
  
  
• Some root vegetables (beets, turnips, potatoes—minimal levels)
  
  

Because phytates are concentrated in the bran or husk, whole grains naturally contain more, but they also offer more nutrients overall.

Preparation helps:

• Soaking, sprouting, fermenting, or sourdough leavening breaks down phytate and enhances mineral absorption.
  
  
• Traditional methods such as fermenting grains or sprouting beans restore bioavailability of calcium, zinc, and iron.
  
  

Phytates don’t need to be eliminated, just managed. When diets include enough minerals and vitamin C, phytate’s impact on bone health is minimal.

Oxalates: The Calcium Binders

Oxalates (oxalic acid) occur naturally in many vegetables and form complexes with calcium that can reduce absorption. In most people, the effect is modest, but high-oxalate diets may contribute to kidney stone risk in those predisposed.

High-oxalate foods:

• Spinach
  
  
• Swiss chard
  
  
• Beets and beet greens
  
  
• Rhubarb
  
  
• Almonds
  
  
• Legumes (moderate)
  
  
• Cereal grains (low to moderate)
  
  

“I used to put frozen spinach in my smoothies every morning. It seemed healthy, but I noticed I didn’t feel good. Once I cut back, those issues improved.” – Dr. Doug Lucas

Spinach and beet greens are the top contributors to dietary oxalate, but boiling and discarding the water reduces levels by 30–90%.

For most people, oxalates are not dangerous, but those with kidney stone history should limit very high-oxalate foods and pair them with calcium-rich foods (e.g., yogurt, cheese) to bind oxalate safely in the gut.

How to Approach Antinutrients Wisely

The goal isn’t to fear plant foods, it’s to prepare them properly and balance your diet.

• Identify high-lectin, high-phytate, or high-oxalate foods.
• Use preparation methods: soak, sprout, ferment, boil, or steam.
• Combine foods smartly, vitamin C enhances mineral absorption; calcium reduces oxalate absorption.
• Pay attention to symptoms: bloating, fatigue, or digestive distress may signal overexposure or imbalance.
• Assess nutrient status through lab testing (e.g., NutraEval or SpectraCell panels).

Modern evidence shows most antinutrients can be neutralized with simple preparation and are only problematic in restrictive, repetitive diets or when nutrient intake is already inadequate.

The Takeaway for Osteoporosis

If your bone density isn’t improving despite “clean eating,” unmanaged antinutrients could play a role, especially if you rely heavily on raw spinach, nuts, or unsoaked legumes.

The fix:

• Cook and prepare food properly.
  
  
• Pair plant foods with minerals and proteins.
  
  
• Monitor symptoms and lab markers.
  
  

“Our ancestors learned how to soak, sprout, and ferment long before supplements existed. Modern bone health depends on bringing those traditions back.” – Dr. Doug Lucas

👉 If you want to learn how to optimize your nutrition for stronger bones, join me in our free OsteoCollective masterclass. I’ll walk you through the biggest diet mistakes I see (including antinutrients) and show you how to build a sustainable bone health strategy. You’ll also have the chance to ask me your questions live during Q&A.

“Our ancestors learned how to soak, sprout, and ferment long before supplements existed. Modern bone health depends on bringing those traditions back.” – Dr. Doug Lucas

👉 If you want to learn how to optimize your nutrition for stronger bones, join me in our free OsteoCollective masterclass. I’ll walk you through the biggest diet mistakes I see (including antinutrients) and show you how to build a sustainable bone health strategy. You’ll also have the chance to ask me your questions live during Q&A.