Skip links

Lectins are everywhere in our modern diets and represent one of the most common ‘hidden’ obstacles faced by individuals on a journey to improve their health. Lectins were identified over a century ago and scientists have reported on their destructive role on human health for over 30 years, yet who ever hears of this food chemical?

A ‘natural pesticide’, lectins exist as another line of self-protection from plants. They discourage over-consumption from predators and therefore decrease the likelihood of extinction for that particular plant. It turns out that not all plants exist purely for our convenience! Who’d have thought!?

All foods contain at least some lectins, although the plants known to contain higher amounts of lectins are:

  • Grains
  • Legumes (apart from peas, green beans and sugarsnap peas)
  • Nuts and seeds
  • Dairy (although grass-fed dairy appears to be OK. More research is required here)
  • Nightshades (tomato, pepper, aubergine and potato)


Not all lectins are bad. The body’s own immune system makes use of its own lectins. Lectins (either those made in the body or those from plants) can actually boost immune activity. However, there are a number of individuals who are already subject to excess immune activity and experience further issues when they eat lectins. These immune-modifying lectins we are talking about relate to two types; prolamines and agglutunins. However, for the sake of simplicity, let’s just call them ‘lectins’.

As with many issues in the health world, they tend to suffer from both generalisations and emotional thinking. This is why we often hear ‘avoid all grains, they are full of toxic lectins’ from one camp and ‘lectins are not a concern as you can just boil them out’. Both are examples of black-and-white thinking and neither are accurate.

Not all lectins are toxic, and most people will not need to avoid them. After all, if all grains were ‘bad’, how would the entire Asian continent thrive with such a high intake of rice? Humans have evolved a system to deal with lectins in food. This centres on digestive secretions like SIgA and mucin, which contain special sugars that the lectins bind with. This sees them form a complex before they interact with the digestive wall. This is why most people can enjoy grains, nuts and beans without any issues. Providing that the overall lectin intake does not overwhelm your capacity to deal with them, you should not expect any trouble.

However, problems occur when the conditions in the digestive tract are disturbed or when stress levels rise. As stress levels increase, SIgA and mucin production drops. This is a recipe for disaster, as these lectins can now bind with the gut lining. This inhibits cell functions and replication. Over time, this will inevitably lead to increased gut permeability. Once this barrier is breached, things go badly wrong. Lectins will bind with glycoproteins all across the body (Wang et al, 1998) and, when they do so, they have a tendency to cause an autoimmune reaction (Cordain et al, 2000).

Lectins have a high affinity for sugars like sialic acid, found extensively in nervous tissue of the gut and the brain. They also love N-acetyl-glucosamine, which just so happens to be a crucial component of the myelin sheath. Anyone with persistant inflammation of the central nervous system should therefore consider their lectin intake. Indeed, animal models suggest lectins may be one of the primary triggers of MS in those susceptible to the disease.

Sialic acid is another crucial target of these lectins. Sialic acid is a vital part of your nervous system and is in large quantities in both the gut and the brain; this may explain why the improvements associated with a low-lectin protocol tend to be dominated by settling of digestive functions and ‘neural’ changes (better sleep, better mood, more energy and sharper thinking). The reality is that lectins will bind with all sort of glycoproteins, and these molecules have roles all across the body but especially regulating the immune system. This can yield huge benefits in immune system function, inflammation and autoimmunity.

So can you process out lectins in your food? There are many corners of the internet that loudly exclaim that prolonged boiling, fermenting, sprouting or soaking will remove these lectins and ensure problem-free access to the nutrients these plants contain. Some claim that you can ‘almost entirely remove lectins by prolonged boiling’ and often back it up with scientific studies, which show the amount of haemagglutinin units drops by over 99% when boiled in water for a sustained period of time (Noah, 1980). The problem is that this study was done on red kidney beans only and these figures may not apply to all other legumes, let alone other families of lectins. For example, we know that soy, peanut and especially wheat agglutinins are much more resistant to traditional cooking methods. As for many of the others, we really do not know for sure. The research has not been done. This creates an environment where impassioned raw-foodies, seduced by a comforting human-centric paradigm that all plants are good and exist only to nourish us, seek solace in this study as it means they need not challenge their held beliefs.

Unfortunately, emotionally-led thinking rarely helps to advance our collective knowledge. Equally, there are plenty of signs in the real world and the evidence strongly suggests that full lectin removal is simply not possible. Many individuals I have worked with have found that they will have problems with almost all high-lectin foods until we have conducted a ‘lectin reset’, where we restrict dietary lectins for three weeks while focusing on supporting the health of the digestive lining and encouraging healthy mucus secretion.

Given that the ‘lectin reset’ requires removal of all the foods above, it is understandably something that few people are keen to undertake. Especially if they have already tried many diets without success. In these instances, it would be ideal to test for lectins before undertaking the diet. The one problem here is that there is no definitive test yet available. We can test for TNF-a, adiponectin and IL-6, and these are highly suggestive of the issue but, at £200 for the three markers, few people choose to pay out for this when they will not provide final confirmation.

The take-home message is that lectins can cause very serious problems but only when our defences are compromised. Not everyone with chronic illness will have issues with lectins, although anyone who has struggled to see the improvements expected in various protocols should consider these as a matter of course. This is especially the case when the symptoms revolve around intestinal issues or brain function.

The removal of lectins can have spectacular effects that are obvious within the first fortnight. If your intestinal cells can take a breather from the inflammatory cascade that lectins trigger, they have a great opportunity to repair themselves. If we can reduce stress on your body in the process, this is a great opportunity to restore the production of mucin and SIgA and therefore restore your resistance to lectins. This often means that individuals will be able to tolerate a very reasonable amount of lectins going forward; while this may mean different things in different people, lectin issues is absolutely not a life sentence. Far from it… it’s much more about short-term reset than long-term removal!

Key points:

  • Many lectins are toxic, but humans have evolved defences against them
  • If these defences are weakened in any way, problems will likely occur
  • Cooking, soaking, fermenting and sprouting will deactivate lectins, but not all of them
  • Once you swallow lectins, they cannot be degraded in the digestive tract
  • Lectins are one of the most common ‘hidden’ causes of health problems
  • Bladderwrack seaweed, N-acetyl-glucosamine and D-mannose have shown a protective effect by binding up various lectins
  • When lectins are confirmed as an issue, avoidance of lectins is rarely necessary long-term, although some moderation is normally a good idea
This website uses cookies to improve your web experience.