Should you avoid gluten?


Should you avoid gluten?

Is gluten as bad as everyone says it is?

Lately there has been a ton of bad press for gluten in the health and fitness community. But is it really as big a blight on your health and your figure as everyone makes it out to be? Or is this just another dieting fad designed to make us to spend over the odds on groceries and take the fun out of eating at restaurants?

Gluten products - bread and cereals

What is gluten?

Gluten is a protein found in wheat and similar grains such as rye, barley, bulgur and oats. It occurs in high proportions in whole grain products, giving them their elasticity and their chewy texture. Gluten can usually be found in foods like pasta, noodles, bread, pastries, cakes, biscuits and cereal.

Celiac disease

Celiac disease is a serious autoimmune disease where the consumption of gluten products causes an adverse reaction. This can lead to abdominal discomfort, diarrhoea and pain in the short term and malabsorption of nutrients, poor growth rate and increased risk of early death in the long term. The only treatment for celiac disease is a gluten free diet.
It is estimated that less than 1% of people worldwide have this condition, although increased screening for celiac disease has seen a rise in those being diagnosed.

Gluten sensitivity

The rate and self-diagnosis of gluten sensitivity is on the rise. Also known as gluten intolerance, this condition can lead to symptoms such as bloating, pain, lethargy and joint pain. Although these symptoms overlap with those seen in celiac disease, they are milder in gluten intolerant individuals. Gluten sensitivity is estimated to affect around 6% of the population in the USA.

What causes gluten-related side effects?

A healthy intestinal tract will absorb food and allow for optimal uptake of nutrients such as proteins to the body. In patients with celiac disease or gluten intolerance, their gastrointestinal problems are related to the fact that gluten, being indigestible to them, can lead to an inflammatory reaction.

This damages the intestinal villi which, over time, can cause the undigested proteins to cross directly through the wall and enter the bloodstream, where a rapid immune system response is induced in an attempt to combat this.

So how do you know if you’re gluten intolerant? Having your blood and stools analysed for the presence of specific antibodies is the only reliable measure. If you experience symptoms such as those listed below after ingestion of gluten products (but not otherwise), you should seek advice from your doctor.

Common symptoms of gluten sensitivity:

•    Nutritional deficiencies 
•    Joint pain
•    Muscular pain
•    Abdominal pain
•    Diarrhoea
•    Bloating and gas
•    Headaches
•    Fatigue

If you present with these symptoms, certainly it is a good idea to try removing gluten from the diet for a few weeks to see if they ease. But what if no symptoms such as these occur? This is where we get on to tricky ground.

The anti-gluten bandwagon

Recently, many major figures in the health and fitness industry have been railing against gluten, arguing that it can cause problems for virtually everyone and recommending that it is avoided regardless of whether you present with the symptoms outlined above. Gluten has been accused of raising cortisol and insulin levels, predisposing the body to fat gain and causing accelerated ageing and decreased thyroid function, amongst other things.

These claims come from people in the mainstream such as Charles Poliquin and Timothy Ferris. Charles Poliquin recommends avoiding gluten for the following reasons:

Gluten free1.    It inflames the brain
2.    Its glutamate content kills brain cells
3.    It has been linked to autism
4.    It is associated with osteoarthritis
5.    It can induce depression
6.    It ramps down your thyroid
7.    It aggravates menopausal symptoms
8.    It is associated with accelerated aging
9.    It exacerbates the symptoms of autoimmune diseases
10.    It weakens tooth enamel and can cause cavities
11.    It negatively affects body composition

To what extent do these claims hold true?

Gluten damages the brain and is linked to autism

It is noted that the brain function of celiac sufferers is more likely to decline over time than that of non-celiac sufferers. Because of this, some people have hypothesised that consuming gluten can damage the brain.

In one study (1), researchers set out to monitor the effects of a gluten and casein free diet (GFCF) on children with autism. Interestingly, the results that came back showed no benefits for sleep, attention or bowel function. It is worth noting that the researchers only selected children who did not have any gastrointestinal issues, so the results may have differed for such individuals.

While poor GI/gluten intolerance has been associated with autism, this is irrelevant for people who have not got autism. It certainly does not mean that all those who ingest gluten can become autistic. 

Related studies demonstrate the fact that neurological impairment resulting from the ingestion of glutens can occur without the commonly noted GI symptoms associated with gluten sensitivity (2), and also that the prevalence of gluten related antibodies such as IgG, IgA or both is much higher in those with neurological dysfunction (3).

The argument that gluten weakens brain function is based on research such as this, where specific antibody testing is used to detect gluten sensitivity even where no GI symptoms may be present. While the case for avoiding glutens is warranted in this case, there is no evidence that gluten causes diminished brain function in those without gluten sensitivity.

Gluten and body composition

It is impossible for anyone to gain fat unless they are in a caloric surplus. That is a basic fact, so the notion that eating grains can lead to fat gain via some other process is false. Underlying this theory is the assumption that in a normal, varied diet that it is the grains that are causing the fat gain and not the meats, nuts, oils and so on, an assumption that we know to be unfounded.

Brown pasta

A review of grain consumption by Giacco et al. (4) linked high grain intake with low BMI (body mass index). Contrary to popular belief, the GI of the grain (whole grain or refined) made no difference. Taking a step back, a comparison of low- and high-carb diets (5) uncovered no significant differences in outcome for body composition.

In another study (6), test subjects with metabolic syndrome who underwent a whole grain-enriched hypocaloric diet experienced a reduction in body fat and cardiovascular risk factors.

If you think about those people who tend to consume a lot of gluten such as vegetarians and people in places like Asia where grains make up a large proportion of the diet, we see that they tend to weigh less than those who eat fewer grain products.

Gluten is associated with osteoarthritis

There is some support for the association between osteoarthritis and gluten consumption. Elkan et al. (7) discovered positive health changes in a group of arthritis patients who went on a gluten-free vegan diet. The researchers remarked:  "A gluten-free vegan diet....induces changes that are potentially atheroprotective and anti-inflammatory, including decreased LDL and oxLDL levels and raised anti-PC IgM and IgA levels."

This study does not tell us which aspect of the gluten-free vegan diet may have contributed to these positive changes, and one cannot be certain whether it was the absence of gluten or of meat and dairy that brought them about. It is also uncertain how these positive health improvements affected the subjects' arthritis.

Other research (8, 9) demonstrates a correlation between gluten consumption and arthritis in celiac patients. If you suffer from arthritis, it may be worth cutting out gluten even if you do not have any other symptoms associated with gluten intolerance.

The fact that some arthritis sufferers might benefit from avoiding gluten does not necessarily mean that arthritis can be caused by gluten in the first place. Nor is it to say that if patients do remove it from their diet, they will experience an improvement in symptoms.

Gluten can induce depression

It may be that gluten sensitive individuals are more prone to depression, but this is very different from saying that gluten can cause depression, especially in those without gluten sensitivity. Research in this area is inconclusive: while some studies demonstrate a link between a gluten-free diet and reduced depression in celiac patients (10), others indicate that it makes no difference for depressed patients but may reduce anxiety (11).

Can gluten cause depression?

Assuming you have no issues with gluten tolerance, the idea that gluten can cause depression demonstrates a gross misunderstanding of the research.

Gluten, thyroid function and autoimmune disease

A substantial body of research supports the idea that having one autoimmune disease increases the likelihood of having another (12, 13, 14), hence the link between celiac disease and thyroid disease. But can gluten consumption contribute directly to thyroid downregulation?

There is no evidence to support this view. For those who are not intolerant to gluten, there is no reason to stop eating grains. Removing gluten from the diet may be beneficial for some people with autoimmune diseases, but we cannot know for certain.

Gluten and ageing

A review of the research uncovers no studies linking gluten with accelerated ageing, unless we count the increased breakdown of physical function seen in celiacs. If you think you can slow down the ageing process by removing gluten from your diet, you’re sorely mistaken. Happily, it’s far simpler than that: all you need to do is eat a balanced, nutrient-rich diet, get plenty of exercise and minimise your intake of toxins such as alcohol and tobacco.

Gluten, PMS and dental decay

There is not much to say here except that unless you are gluten intolerant, there is no evidence to suggest gluten can contribute to these problems. If you suspect that it might be a factor, there’s no harm in eliminating it for a month to see whether or not this makes a difference.

Other claims relating to gluten consumption

Glutens contains phytates, which limit nutrient absorption

Phytates reduce the absorption of nutrients and there is evidence (15) to suggest that big grain consumers such as vegetarians are more likely to suffer from deficiencies in minerals such as zinc. This will be of particular concern to bodybuilders given zinc’s importance for testosterone production.


Having said that, phytates are not only found in food products containing gluten; they are also present in several legumes, nuts and seeds. Suffice to say that unless you plan to live off bread, there is no reason why eating gluten should cause you to experience any nutrient deficiencies.

Gluten causes inflammation

The argument that gluten causes inflammation which in turn causes disease is well known, but is it supported by science? Studies (16, 17) comparing whole grains with refined grains showed an inverse relationship between whole grains (higher in gluten) and inflammation but a positive relationship between refined grains and inflammation.

Lectins in gluten products can cause cellular damage

Lectins are sugar-binding proteins that can interfere with nutrient absorption (18). The pectin content of grains is a concern since as well as interfering with nutrient absorption, pectin can also cause leptin resistance (19). Leptin is a master hormone in the body with a multitude of effects on downstream hormones including testosterone, growth hormone, insulin, cortisol and many others. 

Any interference with this could present significant adverse effects on health and body composition. While this sounds worrying, it should be noted that the majority of data on lectin has come from animal studies. Until adequate research has been conducted on humans, there are no grounds upon which to banish grains and other lectin-containing plant foods from our diets on this basis alone.

Long-term studies

In a study of 23 subjects with type 2 diabetes, Jenkins et al. (20) found that increasing cereal fibre in the diet did not have any effect on glycaemic control or the risk factors for heart disease. Conversely, oxidation of LDL (the so-called ‘bad cholesterol’) in the test phase was greater than that in the control phase.

However, two much larger studies (21, 22) suggest that there may be a link between increased whole grain intake and a reduction in the risk factors associated with cardiovascular disease. The second demonstrated a persistent advantage of high whole grain consumption despite adjusting for other lifestyle factors such as exercise and smoking.

Further research into the effects of grain consumption on health (23, 24, 25) lends additional support to the view that that eating gluten is positively correlated with healthy living.

Healthy breakfast bagel


Many of the allegations made against gluten are based on evidence concerning a small minority of people who have celiac disease and associated illness. These negative traits are being extrapolated to discourage the wider population from eating gluten products.

Many people, including several well-known figures in the health and fitness industry, have overlooked the simple fact that although there may be a link between gluten consumption and the symptoms found in those with certain pathologies, this does not mean that gluten can lead to poor health in the general population.

While there does seem to be a case to limit gluten consumption and rotate carbohydrate sources given the possible adverse effects of lectin, more research is required to verify its impact on humans.

Non-celiac gluten sensitivity does appear to be increasing. This may be a consequence of increased awareness and improved screening as much as a rise in the actual number of people who are intolerant to gluten. If you suspect that you might be sensitive, you could try eliminating gluten from your diet for a month then reintroducing it to confirm whether or not this is the case.

For non-sensitive individuals, the evidence suggests that grain consumption plays a vital role in protecting against everything from heart disease to cancer. As far as we know, including gluten in your diet will do you more good than harm, not only in terms of health but also body composition.




2. Hadjivassiliou M et al. (2002): The humoral response in the pathogenesis of gluten ataxia.
3. Hadjivassiliou M et al. (1996): Is cryptic gluten sensitivity an important cause of neurological illness?
4 Giacco et al. (2011): Whole grain intake in relation to body weight: From epidemiological evidence to clinical trials.
5. Wycherley TP et al. (2010): Long-term effects of weight loss with a very low carbohydrate and low fat diet on vascular function in overweight and obese patients.
6. Katcher et al. (2008): The effects of a whole grain-enriched hypocaloric diet on cardiovascular disease risk factors in men and women with metabolic syndrome.
7. Elkan et al. (2008): Gluten-free vegan diet induces decreased LDL and oxidized LDL levels and raised atheroprotective natural antibodies against phosphorylcholine in patients with rheumatoid arthritis: a randomized study.
8. Bourne, J.T., Kumar, P., Huskisson, E.C. et al. (1985). Arthritis and coeliac disease.
9. Lubrano, E., Ciacci, C., Ames, P.R. et al. (1996). The arthritis of coeliac disease: prevalence and pattern in 200 adult patients.
10. Fera, T et al. (2003): Affective disorders and quality of life in adult coeliac disease patients on a gluten-free diet. 
11. Addolorato G (2001): Anxiety but not depression decreases in coeliac patients after one-year gluten-free diet: a longitudinal study.
12. Collin P et al. (1994): Autoimmune thyroid disorders and coeliac disease.
13. Hakanen M et al. (2001): Clinical and subclinical autoimmune thyroid disease in adult celiac disease.
14. Akcay MN et al. (2003): The presence of the antigliadin antibodies in autoimmune thyroid diseases.
15. Hunt JR (2002): Moving toward a plant-based diet: are iron and zinc at risk? 
16. Qi L et al (2006): Whole-grain, bran, and cereal fiber intakes and markers of systemic inflammation in diabetic women.
17. Jensen MK et al (2006): Whole grains, bran, and germ in relation to homocysteine and markers of glycemic control, lipids, and inflammation.
18. Cordain et al. (1999): Modulation of immune function by dietary lectins in rheumatoid arthritis.
19. Jonsson et al. (2009): Agrarian diet and diseases of affluence – Do evolutionary novel dietary lectins cause leptin resistance?
20. Jenkins DJ et al. (2002): Effect of wheat bran on glycemic control and risk factors for cardiovascular disease in type 2 diabetes.
21. Majken K Jensen et al. (2004): Intakes of whole grains, bran, and germ and the risk of coronary heart disease in men.
22. Jacobs et al. (2004): Reduced mortality among whole grain bread eaters in men and women in the Norwegian County Study.
23. D R Jacobs et al. (1999): Is whole grain intake associated with reduced total and cause-specific death rates in older women? 
24. Liu et al. (1999): Whole-grain consumption and risk of coronary heart disease.
25. Shatzkin et al. (2007): Dietary fiber and whole-grain consumption in relation to colorectal cancer in the NIH-AARP Diet and Health Study.