How Antinutrients Wreck Your Healthy Diet

You may never have heard of them before but antinutrients could be the thing wrecking your healthy diet.

So if you eat healthily but struggle with the tell tale signs of nutritional deficiency - fatigue, stress and weak immunity - read on. Antinutrients may be an explanation, they were for me.

Antinutrients are natural compounds in food - mostly plants - that can grab onto key nutrients and stop our body absorbing them fully, leaving us short.

In this guide covering everything I learned the hard way about antinutrients, I'll take you through :

1. Nutritional Deficiencies
2. Diets Vulnerable To Antinutrients
3. Other Underlying Risks
4. Different Types Of Antinutrients
5. Foods They Hide In
6. How To Cut Their Impact

I hope the guide helps you get to the bottom of what is sabotaging your healthy diet. Do bookmark or save on Pinterest to come back to.

NB I have NO medical qualifications. This is NOT medical advice. See a doctor if you have health concerns.

Key Nutritional Deficiencies

The key nutritional deficiencies caused by antinutrients in our diet are :

1. Iron
2. Zinc
3. Magnesium
4. Calcium

Every single cell in our body needs the first three and most need calcium. So if antinutrients leave us even a little bit deficient we really will feel it!

Iron

We need iron for energy and healthy blood. Low levels can leave us drop dead exhausted and trigger all sorts of other surprising symptoms.

Zinc

Our immune system, gut, skin, hair and more all depend on zinc - shortages can mean more colds or slow healing plus acne, weak hair and more.

Magnesium

Our nervous system, hormones and muscles all rely on magnesium. Going short can mean stress, inflammation, poor sleep and severe period pain.

Calcium

A shortfall in calcium isn't just bad for bones and teeth, it can also cause muscle cramps, tingling, memory problems, lethargy and more.

If you eat plenty of these but don't see the benefits antinutrients could be the sneak thief stealing your supply!!

Types Of Antinutrient

The four antinutrients most likely to be pillaging from your plate are :

1. Phytates (Phytic Acid)
2. Oxalates (Oxalic Acid)
3. Lectins
4. Tannins

Some others e.g.s Glucosinolates, Goitrogens impact iodine levels and thyroids but not as significantly.

Phytates

Phytates act like little nutrient snatchers in our gut. They bind to iron, zinc, magnesium, and calcium, making it harder for our body to absorb them and can nab as much as 50% of these nutritional goodies per meal.

Oxalates

Oxalates are sneaky compounds in our food that latch onto calcium—and sometimes iron—in our gut, forming crystals our body can’t use.

Normally, this just means a bit less calcium or iron from that meal (10-30% drop) - no biggie in a balanced diet.

But if we devour tons of raw oxalates those crystals may build up in :

• Kidney stones if we are at risk
• Painful joints if we've got a dodgy gut from SIBO, gastritis.

Lectins

Lectins are proteins that can stick to, irritate and damage our gut lining.

This damage lets nutrients like iron, zinc and calcium slip through the cracks instead of getting absorbed - think 10-20% less uptake in bad cases.

If you've been devouring huge amounts of raw lectins on veggie and vegan diets or suffering with gut problems from too much sugar they can hurt!

Tannins

Tannins - the bitter bits in tea, coffee & wine - can grab onto iron in our gut, especially the plant-based kind, cutting absorption by 50-70% per meal.

It’s a problem if we're low on iron already especially for veggie lovers or during our period when iron’s precious.

Diets Vulnerable To Antinutrients

Some diets are especially vulnerable to the impact of antinutrients and resulting nutritional deficiency :

1. Vegetarian & Vegan
2. Plant Heavy Diets
3. Low Diversity Diets
4. Some Low Carb Diets

Vegetarian & Vegan

Vegetarians and vegans are vulnerable to iron and zinc deficiency because plants are just not as rich in these minerals as food from animals.

But it is a double bind : food they need to eat for protein and other vitamins e.g. grains, beans, nuts are high in iron and zinc blocking antinutrients.

And even supplements aren't safe from the pillaging. Phytic acid can steal 50-90% of their iron - a real haul!!

Plant Heavy Diets

Even meat eaters can feel the pinch on available iron if they eat lots of plant food and enjoy tannin rich drinks.

The hit is less as we get more iron from meat to start with but if we only eat red meat once a week we can go short.

Low Diversity Diets

If we over rely on a few foods rich in antinutrients day in, day out they can build up in our body and cause big problems e.g. kidney stones!

Low Carb Diets

Lots of Keto diets use almond flour for cookies, cakes etc. That's fine in moderation but over do it and high oxalates can be a time bomb!

Other Underlying Risks

Some people have no problem with pretty high levels of antinutrients in unbalanced elimination diets.

But some of us are more vulnerable. So keep an extra eye on them if you have :

• Iron deficiency issues
• SIBO
• Leaky gut problems
• Kidney stone history
• Chronic inflammation
• Celiac issues
• Diet related autoimmune problems.

That sounds all doom and gloom but there are super simple ways to slash the impact of antinutrients which our grannies knew back in the day!!

I'll cover the quick fixes shortly but let's look first at food antinutrients hide in.

Foods Rich In Antinutrients

Antinutrients hide mostly - of course they would!! - in pretty nutritious food :

1. Grains
2. Legumes
3. Nuts & Seeds
4. Vegetables
5. Fruit
6. Drinks

Grains

Lots of common grains especially the wholegrain varieties are high in phytates and lectins :

• Wheat
• Corn (maize)
• Oats
• Brown rice
• Millet
• Quinoa
• Barley
• Sorghum

White rice is lower in antinutrients but less nutritious so it is a trade off.

Legumes

Sadly the legumes, vegetarians and vegans rely on for protein, are chock full of phytates, lectins and tannins. The worst culprits are :

• Soybeans
• Kidney beans
• Black beans
• Lima beans
• Chickpeas
• Peanuts.

These legumes are lower but still high :

• Lentils
• Green peas
• Mung beans.

Nuts & Seeds

Nuts and seeds are themselves little power houses of nutrients BUT are full of all four main antinutrients.

These nuts & seeds are very sadly some of the worst culprits :

• Almonds
• Walnuts
• Brazil nuts
• Cashews
• Sesame seeds
• Chia
• Flax

Oxalate as we've seen can be a real problem in almonds if you are eating loads of almond flour on a Keto diet or guzzling almond milk. Especially if you are also overdoing oxalate rich veggies.

Vegetables

Personally, I love veggies!! I grow spinach, kale and tomatoes in my garden and they are full of great stuff.

But we must acknowledge they do have strong kleptomaniac tendencies!!

On veggie, vegan and low red-meat diets, these antinutrient veg can be an issue if not prepared properly :

• Spinach
• Kale
• Beets
• Swiss Chard
• Broccoli
• Brussels Sprouts
• Sweet Potatoes
• Tomatoes
• Potatoes

Fruit

Fruit again - especially berries - are antioxidant powerhouses for colds etc but as ever we can have too much of a good thing stuffing ourselves with these tannin rich babies :

• Blackberries
• Raspberries
• Blueberries
• Grapes
• Pomegranates
• Apples
• Pears
• Kiwi
• Rhubarb
• Starfruit

Drinks

A bunch of our favourite drinks are sadly high in tannins which thieve iron :

• Black Tea
• Green Tea
• Oolong Tea
• White Tea
• Red Wine
• Rosé Wine (less than red)
• Coffee (lower than tea but present)
• Pomegranate Juice
• Grape Juice (especially red)
• Cranberry Juice
• Apple Cider (unfiltered)

Now they won't be a problem with your chuck steak - full of heme iron - but they can nick a load of the non-heme iron in your vegan meal!!

So what on earth should we do?

Well luckily there are easy ways to invite antinutrients for dinner without them making off with the family silver!!

Best Ways To Cut Impact

The four must know ways - your granny knew - to reduce the impact of antinutrients on nutrition are :

1. Soaking
2. Cooking Well
3. Food Combining
4. Fermenting

Soaking

Soaking grains and legumes is a simple trick to cut down on antinutrients so you get more nutrients and less gut ache. Here’s the quick scoop on :

• Grains
• Legumes
• How Much Reduced
• Canned Legumes

Grains

Soak grains rice, oats, quinoa in warm water for 6-12 hours (overnight’s perfect). Cuts phytic acid by 20-50%—more if you add a splash of lemon juice or vinegar to help break it down.

Legumes

Soak beans, lentils & chickpeas in cool or warm water for 8-24 hours (kidney beans need the full 24, lentils can do 8). Drops phytic acid 30-50% and lectins by 50-80%. Change water once or twice.

How Much Reduced?

Depends on time and temp, but you’re looking at 30-60% less antinutrients overall -enough to boost iron and zinc uptake noticeably.

Canned Legumes

No soaking needed! They’re pre-cooked and rinsed, slashing antinutrients by 50-90% already—phytic acid’s low, lectins are toast. Just drain and go.

Cooking Well

Cooking our veggies, fruits, nuts, seeds, grains, and legumes the right way can dial down those antinutrient so we get more goodness out of every bite.

The quick lowdown is quick boil greens, stew fruit, roast nuts and slow cook legumes but for more details :

• Vegetables
• Fruit
• Nuts & Seeds
• Grains
• Legumes

Vegetables

Boil leafy greens e.g. spinach, kale, beet leaves for 5-10 minutes to cut oxalates by 30-50%. Drain the water well.

Roast tomatoes for 10-20% minutes to slash lectins 90%. No need to peel.

Fruits

Lightly stew e.g. berries, apples, pears for 10-20 minutes to soften tannins and reduce their impact by 20-30%.

Nuts & Seeds

Dry roast nuts & seeds at 300f/150c for 10-15 mins to clear lectins and reduce phytic acid by 20-40%.

Grains

Boil and simmer rice, oats and quinoa for 20-40 minutes after soaking which together will cut phytic acid by 40-60%.

Legumes

Boil - simmer lentils for 30 minutes and beans & chickpeas for 90 minutes to reduce - with soaking - lectins by 90% and phytic acid by 40-60%.

Food Combining

Lots of traditional cooking combines food in clever ways to reduce antinutrient impact e.g.

• Spinach & Dairy
• Beans & Rice
• Tea & Lemon
• Nuts & Fruit
• Whole Grains, Onions & Garlic
• Tomatoes & Olive Oil
• Lentils & Bell Peppers

These combos pair antinutrient-heavy foods with helpers calcium, vitamin C or fats - to dodge the blocks and boost what you get out of your meal.

Spinach & Dairy

Serving spinach with lots of dairy - think creamed spinach, spinach & cheese sauce - allows the spinach to steal some calcium without leaving you short and stops the oxalates from nicking other stuff!

Beans & Rice

Rice’s low phytic acid balances beans’ higher levels, plus amino acids complement each other for better protein use.

Tea & Lemon

Vitamin C in lemon boosts iron absorption, countering tannins in tea that bind it.

Nuts & Fruit

In all those great nut & fruit combos e.g. almonds & oranges, vitamin C in fruit offsets phytic acid in nuts, improving iron and zinc uptake.

Whole Grains, Onions & Garlic

Sulfur compounds in onions and garlic enhance mineral absorption, softening phytic acid’s grip on grains.

Tomatoes & Olive Oil

Fat in olive oil helps absorb nutrients, diluting the gut disruption of lectins in tomatoes.

Lentils + Bell Peppers

Vitamin C in peppers counters phytic acid in lentils, unlocking more iron and zinc.

It is worth checking out old cook books for more ideas. There is a lot of nutritional wisdom in the old combos e.g. pork & sauerkraut, fish & parsley sauce, turmeric & black pepper, lentils & yoghurt we can learn lots from!!

Fermenting

Without getting into fancy fermenting there are some super simple fermented food choices you can make to help you enjoy nutritious food without antinutrients stealing your lunch!!

The two easiest choices are :

• Sourdough Bread
• Lacto Fermented Vegetables

Sourdough Bread

Fermentation in sourdough bread cuts:

• Phytic acid : 50-70%
• Lectins : 30-50%
• Tannins : 10-20%

So a sourdough meat sandwich could give you 2 to 3 times better iron and zinc absorption than standard bread!!

Lacto Fermented Vegetables

If you are vulnerable to e.g. iron deficiency or zinc deficiency from phytic acid, lacto fermented vegetables can be a great choice.

Fermentation lets phytic acid run off with 50-70% less goodies in a meal than raw or barely cooked veg.

And there you go, all the stuff I have learned about how stop antinutrients stealing nutrition from a healthy diet.

Do bookmark the guide or save on Pinterest to come back to later.

Please remember I am not medically qualified and this is not medical advice. I am always learning and mistakes. Do shout if you spot howlers!

For more simple healthy eating advice check out my other nutrition guides and follow me on Pinterest.