Problem foods and beverages


There are many foods and beverages which can contribute to mental health problems when they are consumed regularly, or even sporadically, especially if you are sensitive or intolerant to them. These can be divided roughly into the following categories:

Allergenic foods and beverages

There are two types of allergic reaction:

  • An actual food allergy which involves an immune response following exposure to a particular food
    • Manifestations include skin reactions such as itching, sensitivity or swelling in the mouth, breathing problems, and neurological problems like anxiety and confusion
    • It is more serious and more immediately visible than food intolerance
  • A food intolerance which does not involve the immune system in the same way, though can still cause inflammation and gut issues
    • Usually due to an enzyme deficiency (lactose deficiency for instance), poor intestinal integrity (leaky gut), gut dysbiosis, or a reaction to additives, and can contribute to mental health problems such as mood changes, anxiety and fatigue

Foods and beverages containing toxins

  • Pesticides, herbicides, chemical additives such as colours, preservatives, flavouring (eg: monosodium glutamate (MSG) which has an excitatory effect on the nervous system) can all cause inflammation and toxicity, which can lead to mental health issues

Stimulating and addictive foods and beverages

  • Sugar, caffeine, alcohol which all act as stimulants, and can be addictive and over-stimulating to the nervous system
  • Can cause blood sugar imbalances

Kohlboeck, G., Sausenthaler, S., Standl, M., Koletzko, S., Bauer, C, von Berg, A., Berdel, D., Krämer, U., Schaaf, B., Lehmann, I., Herbarth, O. and Heinrich, J. (2012). Food intake, diet quality and behavioral problems in children: results from the GINI-plus/LISA-plus studies. [online] Annals of Nutrition and Metabolism, 60 (4), pp. 247–256. Available at: [accessed 24 Aug. 2017]., Zahedi, H., Kelishadi, R., Heshmat, R., Motlagh, M., Ranjbar, S., Ardalan, G., Payab, M., Chinian, M., Asayesh, H., Larijani, B. and Qorbani, M. (2014). Association between junk food consumption and mental health in a national sample of Iranian children and adolescents: The CASPIAN-IV study. [online] Nutrition, 30 (11), pp. 1391–1397. Available at: [accessed 24 Aug. 2017].

Allergenic foods and beverages

These are foods which can cause an obvious allergic reaction involving the immune system, or a milder intolerance or sensitivity – all of which can cause inflammation, gut issues and mental health issues in sensitive individuals De Theije, C., Bavelaar, B., Lopes da Silva, S., Korte, S., Olivier, B., Garssen, J. and Kraneveld, A. (2014). Food allergy and food-based therapies in neurodevelopmental disorders. [online] Pediatric Allergy and Immunology, 25 (3), pp. 218–226. Available at: [accessed 24 Aug. 2017]..

While an allergic reaction to a food or beverage tends to be obvious immediately, an intolerance or sensitivity can be much harder to identify, with symptoms which can be non-existent, or ranging from mild to severe.

Seven foods cause about 90% of all food intolerance reactions:

  • Milk and milk products which contain the milk proteins casein and whey and the milk sugar lactose which are common allergens
    • Fermented milk products such as kefir and yoghurt can be more easily digestible
    • Goat and sheep milk can be more digestible than cow’s milk
  • Wheat and other grains with gluten, including barley, rye, spelt and oats
    • Celiac disease is the more extreme case of wheat allergy, however wheat and gluten can also cause milder intolerances which can cause low grade inflammation and which test negative on a gluten intolerance (celiac) test
  • Eggs
  • Soy
  • Fish
  • Shellfish
  • Nuts
    • Ground nuts: peanuts
    • Tree nuts: such as walnuts, almonds, pine nuts, brazil nuts, and pecans

Almost any food can trigger an intolerance however. Less common ones include:

  • Corn
  • Gelatin
  • Meat – beef, chicken, mutton, and pork
  • Seeds, often sesame, sunflower, and poppy
  • Spices, such as caraway, coriander, garlic, and mustard
  • Celery

(2017). Common Food Allergy Triggers. [online] WebMD. Available at: [accessed 27 Oct. 2017].

  • Anxiety
  • Fatigue
  • Brain fog
  • Mood swings
  • Depression
  • Insomnia

Ranges from asymptomatic to the following:

  • Bloating
  • Diarrhea
  • Cramping
  • Gas
  • Raised heart beat immediately after eating

An undiagnosed intolerance can cause a situation of chronic inflammation leading to gut issues, poor digestion and absorption, which can contribute to or exacerbate mental health conditions such as depression and anxiety Burks, A., Tang, M., Sicherer, S., Muraro, A., Eigenmann, P., Ebisawa, M., Fiocchi, A., Chiang, W., Beyer, K., Wood, R., Hourihane, J., Jones, S., Lack, G. and Sampson, H. (2012). ICON: food allergy. [online] Journal of Allergy and Clinical Immunology, 129 (4), pp. 906–920. Available at: [accessed 24 Aug. 2017]..


Unlike a food intolerance, severe food allergies such as peanut allergy and celiac disease (allergy to gluten) can be identified with a blood test, and are a far more serious condition than a sensitivity or intolerance.

Intolerances and sensitivities

To identify an intolerance or sensitivity, you can take a food intolerance test, which is usually a pin-prick blood test, however the reliability and accuracy of these have been questioned.

Another cheaper and possibly more reliable but more time consuming method is to follow an elimination diet, in which you eliminate potentially all allergenic foods from your diet for two to four weeks, and then systematically reintroduce them one by one, taking note of any symptoms in a food and mood journal during both elimination and reintroduction phase.

If you feel better during the elimination phase, but start to feel unwell or develop symptoms during the reintroduction phase, it is a strong indication that you are allergic or intolerant to a specific food Greenblatt, J. (2011). The Breakthrough Depression Solution. North Branch, MN: Sunrise River Press, pp. 107-121..

A urine test can check for casein, whey and lactose intolerance.

Gluten is a protein found in:

  • Wheat (including wheat varieties like spelt, kamut, farro and durum, bulgur and semolina)
  • Barley
  • Rye
  • Triticale
  • Oats (unless they are “gluten free”)

(2017). Gluten in Grains. [online] Grains & Legumes Nutrition Council. Available at: [accessed 27 Oct. 2017].

When you are sensitive to gluten, consuming it can trigger an immune response, leading to inflammation Kharrazian, D. (2013). Why Isn’t My Brain Working? CA: Elephant Press, p. 124.:

  • This is usually due to an inability to properly digest gliadin, a protein found in gluten
  • Undigested gliadin produces gliadorphin which acts as a neuropeptide
    • Neuropeptides cause the release of neurotransmitters such as adrenaline, noradrenaline and dopamine affecting mood, and possibly causing anxiety and depression
    • Gliadorphin is an opioid peptide, which has an effect on motivation, emotions and attachment behaviour Honeyman, J. F. (2016). Psychoneuroimmunology and the Skin. [online] Acta Dermato-Venereologica, 96 (217), pp. 38-46. Available at: [accessed 30 Aug. 2017].
  • Left undiagnosed, a gluten sensitivity can damage your gut lining and prevent the optimal absorption of nutrients
  • In some people, gliadin can produce a similar effect to the antibodies that attack the thyroid gland in autoimmune conditions
    • While one condition has nothing to do with the other, the symptoms are often the same – fatigue, loss of enthusiasm, mild to moderate depression, unexplained weight gain and hair loss
    • In cases where these symptoms are present but thyroid tests all prove to be normal, always recommend that clients have a gliadin sensitivity test Gluck, M. and Edgson, V. (2010). It Must Be My Hormones. Camberwell, Vic.: Penguin Group (Australia), p. 186.
  • Studies have shown that gluten sensitivity can cause disorders in the digestive system and gut, but also in the following areas attaining to mental health:
    • Brain
    • Mood
    • Spinal cord
    • Peripheral nerves

    Kharrazian, D. (2013).Why Isn’t My Brain Working? CA: Elephant Press, p. 159., Peters, S., Biesiekierski, J., Yelland, G., Muir, J. and Gibson, P. (2014). Randomised clinical trial: gluten may cause depression in subjects with non‐coeliac gluten sensitivity–an exploratory clinical study. [online] Alimentary Pharmacology & Therapeutics, 39 (10), pp. 1104–1112. Available at: [accessed 24 Aug. 2017].

Possible mental health symptoms of gluten sensitivity

  • Lethargy
  • Poor focus
  • Depression
  • Anxiety
  • Craving for gluten-containing products
  • Irritability
  • Autistic symptoms
  • Brain fog
  • Insomnia

Kharrazian, D. (2013). Why Isn’t My Brain Working? CA: Elephant Press, p. 123.

Gluten sensitivity has also been (controversially) implicated in some neuropsychiatric disorders, including:

  • Schizophrenia
    • Schizophrenia’s original name was “Bread Madness” on account of the observation that schizophrenic patients who eat gluten have a higher degree of neurological symptoms and schizophrenic exacerbation Scott, T. and Osborne, P. (May 2015). Grainflammation – How Grain Consumption Contributes to Anxiety and Mood Disorders. [online] The Anxiety Summit, Season 3. Available at:
  • Eating disorders
  • Autism
  • Peripheral neuropathy
  • Ataxia
  • Attention deficit hyperactivity disorder (ADHD)

Fasano, A., Sapone, A., Zevallos, V. and Schuppan, D. (2015). Nonceliac gluten sensitivity. [online] Gastroenterology, 148 (6), pp. 1195–204. Available at: [accessed 29 Aug. 2017]., Catassi, C., Bai, J.C., Bonaz, B., Bouma, G., Calabrò, A., Carroccio, A., Castillejo, G., Ciacci, C., Cristofori, F., Dolinsek, J., Francavilla, R., Elli, L., Green, P., Holtmeier, W., Koehler, P., Koletzko, S., Meinhold, C., Sanders, D., Schumann, M., Schuppan, D., Ullrich, R., Vécsei, A., Volta, U., Zevallos, V., Sapone, A. and Fasano, A. (2013). Non-celiac gluten sensitivity: the new frontier of gluten related disorders. [online] Nutrients, 5 (10), pp. 3839-53. Available at: [accessed 29 Aug. 2017]., Lebwohl, B., Ludvigsson, J. F. and Green, P. H. (2015). Celiac disease and non-celiac gluten sensitivity. [online] BMJ, 351, h4347. Available at: [accessed 29 Aug. 2017]., Volta, U., Caio, G., De Giorgio, R., Henriksen, C., Skodje, G. and Lundin. K.E. (2015), Non-celiac gluten sensitivity: a work-in-progress entity in the spectrum of wheat-related disorders. [online] Best Practice and Research, Clinical Gastroenterology, 29 (3), pp. 477–91. Available at: [accessed 29 Aug. 2017]., Aziz, I., Hadjivassiliou, M. and Sanders, D. S. (2015), The spectrum of noncoeliac gluten sensitivity. [online] Nature Reviews. Gastroenterology & Hepatology, 12 (9), pp. 516–26. Available at: [accessed 29 Aug. 2017].

Wheat also contains carbohydrates called fructans and proteins called lectins both of which can be irritating to the gut and cause intolerances.

Celiac disease is a far more serious condition than gluten sensitivity, and involves an allergy to gluten.

It is a serious auto-immune disease, and occurs when the body mounts an immune attack because it mistakes gluten for a dangerous toxin and aims to destroy it, damaging the small intestine in the process.

When this occurs, food can’t be properly broken down, and nutrients can’t be absorbed.

This can lead to a deficiency in various key amino acids and micronutrients, which can affect neurotransmitters such as serotonin, dopamine and GABA which can lead to:

  • Depression
  • Anxiety and panic
  • Sleep issues
  • Poor attention
  • Poor memory
  • Apathy
  • Irritability

van Hees, N. J. M., Giltay, E. J., Tielemans, S. M. A. J., Geleijnse, J. M., Puvill, T., Janssen, N. and van der Does, W. (2015). Essential amino acids in the gluten-free diet and serum in relation to depression in patients with celiac disease. [online] PloS One, 10 (4), e0122619. Available at: [accessed 30 Aug. 2017].

Fermentable, Oligo-, Di-, Mono-saccharides and Polyols (FODMAPs) are short chain carbohydrates that are poorly absorbed in the small intestine. They can be found in a range of different foods:

  • Oligo-saccharides: e.g. fructans (found in wheat, rye and some vegetables) and galacto-oligosaccharides (found in pulses and legumes)
  • Di-saccharides: e.g. lactose (found in mammalian milk)
  • Mono-saccharides: e.g. free fructose (found in honey, some fruit and fruit juices)
  • Polyols: e.g. sorbitol and mannitol (found in some fruits and vegetables)

(2017). Information on the low FODMAP diet. [online] King’s College London. Available at: [accessed 27 Oct. 2017].

A full list can be found here.

Patients with IBS suffering from bloating, abdominal pain and diarrhoea often show improvement in these symptoms by following the FODMAP diet Chey, W., Kurlander, J. and Eswaran, S. (2015). Irritable bowel syndrome: a clinical review. [online] JAMA, 313 (9), pp. 949–958. Available at: [accessed 24 Aug. 2017]..

There is often a correlation between IBS and mental health symptoms such as depression, anxiety, lethargy, irritability, etc.

Dairy can cause several types of intolerance.

Casein intolerance

Casein is a milk protein found in dairy products, and is a common allergen which some people have a hard time digesting. Its metabolite casomorphin can affect the brain and cause mental health symptoms, having opioid like properties Sharma, N., Sharma, V., Nautiyal, S. C., Singh, P. R., Kushwaha, R. S., Sailwal, S., Shayan, G., Ahmer, N. and Singh, R. K. (2012). A1, A2 Beta casein variants in cows – its impact on modern human health. [online] International Journal of Research in Social Sciences, 2 (4), pp. 705-18. Available at: [accessed 29 Aug. 2017].:

  • Casomorphin, like gliadorphin is an opioid neuropeptide
  • It affects behaviour by attaching to opioid receptors in the brain
  • Abnormal opioid activity leads to behavioural problems as well as deficits in attention and social communication which are features of autism, and is also implicated in Parkinson’s disease and schizophrenia Saeed, U., Ishaq, M., Zil-E-Ali, A., Zafar, H. and Zafar, S. (2016). Peptides, gluten, casein and autistic behavior – a review. [online] Professional Medical Journal, 23 (7), pp. 766-9. Available at: [accessed 29 Aug. 2017].
  • Casomorphin has been consistently shown to be elevated in postpartum psychosis Tveiten, D. and Reichelt, K. L. (2012). Exorphins in urine from schizoaffective psychotics. [online] Open Journal of Psychiatry, 2, pp. 220-7. Available at: [accessed 29 Aug. 2017].
  • The link between depression and casomorphin is uncertain, however tests have shown that people with depression tend to have more casomorphin than non-depressed people

Lactose intolerance

If you have a deficiency of the enzyme lactase, then you cannot properly digest the lactose found in dairy products.

Patients with IBS are more likely to suffer from lactose intolerance.

Patients with IBS and gut sensitivity tend to have higher levels of anxiety Yang, J., Fox, M., Cong, Y., Chu, H., Zheng, X., Long, Y., Fried, M. and Dai, N. (2014). Lactose intolerance in irritable bowel syndrome patients with diarrhoea: the roles of anxiety, activation of the innate mucosal immune system and visceral sensitivity. [online] Alimentary Pharmacology & Therapeutics, 39 (3), pp. 302–11. Available at: [accessed 29 Aug. 2017]..

Legumes, which include beans, peas, lentils and peanuts, are a healthy source of complex carbohydrates, protein and fibre, but some people find them difficult to digest and can have intolerance reactions.

The two adverse or ‘toxic’ factors contained in legumes are lectins and phytates. Both are termed by some nutritionists as ‘anti-nutrients’, because they can prevent the absorption of nutrients.

Toxic foods and beverages

As well as working out whether you might have an allergy or intolerance to certain foods (in which case the foods and beverages to which you are intolerant are toxic for you), there are certain toxic foods which should be avoided for optimal mental health.

Trans fats, or trans-fatty acids, and some saturated fats, can be detrimental to mental health. Both trans-fatty acids and saturated fats can make your brain cells hard and rigid and interfere with the brain’s ability to process information quickly Perlmutter, D. and Colman, C. (2004). The Better Brain Book. New York: Riverhead Books, p. 26..

Trans fats

Trans fats, or hydrogenated fats, are bad fats, with no health benefits whatsoever:

  • They are found in processed or fried foods and certain vegetable oils such as hydrogenated vegetable oils
  • Trans fats compete with, damage and block the conversion of healthy Essential Fatty Acids such as GLA, DHA, EPA and prostaglandins, preventing them from doing their vital brain-protecting work Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p. 42, p. 79.
  • Trans fats are implicated in Alzheimer’s disease by contributing to beta amyloid production in the brain Barnard, N., Bush, A., Ceccarelli, A., Cooper, J., de Jager, C., Erickson, K., Lucey, B., Morris, M. and Squitti, R. (2014). Dietary and lifestyle guidelines for the prevention of Alzheimer’s disease. [online] Neurobiology of Aging, 35, S74–S78. Available at: [accessed 25 Aug. 2017].

Trans fats or hydrogenated fats are found in most:

  • Crackers
  • Crisps
  • Cakes
  • Sweets
  • Biscuits
  • Doughnuts
  • Processed cheese

Processed oils such as:

  • Corn
  • Safflower
  • Sunflower
  • Peanut
  • Canola
  • Rapeseed

The wrong type of saturated fats

Higher saturated fat is associated with cognitive decline, as well as depression Jacka, F., Sacks, G., Berk, M. and Allender, S. (2014). Food policies for physical and mental health. [online] BMC Psychiatry, 14 (1), p. 132. Available at: [accessed 25 Aug. 2017]., Jørgensen, B., Hansen, J., Krych, L., Larsen, C., Klein, A. B., Nielsen, D., Josefsen, K., Hansen, A. and Sørensen, D. (2014). A possible link between food and mood: dietary impact on gut microbiota and behavior in BALB/c mice. [online] PLoS One, 9 (8), e103398. Available at: [accessed 25 Aug. 2017]..

However, saturated fats are not all created equal. Indeed there are bad saturated fats, from unhealthy sources (from the produce and processing of industrially raised meat and poultry), and good saturated fats, from healthy sources (grass fed, free range, organic, unprocessed produce of meat, poultry and dairy, coconut oil, avocado, nuts, dark chocolate, etc.) Harvard Health Publications: Harvard Medical School, (2015). The truth about fats: the good, the bad, and the in-between. [online] Available at: [accessed 25 Aug. 2017]., Levine, B. (2012). Fats and Brain Function. [online] Baseline of Health Foundation. Available at: [accessed 30 Aug. 2017].. While the wrong types of saturated fats should be avoided, due to their negative health consequences, the right types of saturated fats and cholesterol are essential for optimal mental health.

Most processed foods, in a box, can or bottle are full of artificial food additives and chemicals to flavour, colour, texture and preserve your food.

In high concentrations, some of these additives and chemicals can contribute to adverse mental health symptoms, such as hyperactivity and depression, and should be avoided:

  • Monosodium glutamate
  • Food colourings Nigg, J. T., Lewis, K., Edinger, T. and Falk, M. (2012). Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives. [online] Journal of the American Academy of Child & Adolescent Psychiatry, 51 (1), pp. 86–97. Available at: [accessed 29 Aug. 2017].
  • Sodium benzoate-rich beverages as seen in carbonated drinks are associated with ADHD-like behaviour in college students Beezhold, B. L., Johnston, C. S. and Nochta, K. A. (2014). S Sodium benzoate-rich beverage consumption is associated with increased reporting of ADHD symptoms in college students: a pilot investigation. [online] Journal of Attention Disorders, 18 (3), pp. 236–41. Available at: [accessed 29 Aug. 2017].
  • Non-organic meats
    • Beef, chicken, etc. can contain growth hormone, antibiotics, and pesticide and herbicide residue which can be detrimental to our mental health
  • Organ meats
  • Fish
    • Large ocean fish
      • Tuna, swordfish, shark, tilefish can contain high levels of mercury which can be damaging to mental health
    • River fish
    • Heavy metals such as mercury, lead and aluminum levels are positively correlated with maternal fish consumption
      • The mean levels of these heavy metals is higher in the hair of autistic children
    • Fish consumption is also associated with consumption of cadmium through pollution and is positively associated with depression Berk, M., Williams, L., Andreazza, A., Pasco,J., Dodd, S., Jacka, F., Moylan, S., Reiner, E. and Magalhaes, P. (2014). Pop, heavy metal and the blues: secondary analysis of persistent organic pollutants (POP), heavy metals and depressive symptoms in the NHANES National Epidemiological Survey. [online] BMJ Open, 4 (7), e005142. Available at: [accessed 18 Aug. 2017].
  • Non-organic fruit and vegetables
  • Soy
    • Soy can be damaging to the gut through a component called the trypsin inhibitor
      • Trypsin is the enzyme we need to digest protein effectively
      • Soy not only inhibits the process, but is itself high in protein
      • The inability to digest it can cause stress on the pancreas and lead to pancreatitis
      • Chronic pancreatitis can cause mental distress including anxiety
    • Soybeans and their food products (Tofu) have been investigated for potential benefit against Alzheimer’s disease, however current evidence shows that soybeans can lead to cognitive impairment Chatterjee, G., Roy, D., Khemka, V. K., Chattopadhyay, M. and Chakrabarti, S. (2015). Genistein, the isoflavone in soybean, causes amyloid beta peptide accumulation in human neuroblastoma cell line: Implications in Alzheimer’s disease. [online] Aging and Disease, 6 (6), pp. 456-65. Available at: [accessed 30 Aug. 2017].
    • Soy has been said to cause anxiety (possibly due to soy’s estrogenic effects)
    • Soy has been associated with ADD and learning
    • Soy has also been linked to thyroid problems, the symptoms of which include lethargy, malaise and fatigue Scott, T. and Daniel, K. (May 2015). Real food for Anxiety: Butter, Broth and Beyond. [online] The Anxiety Summit, Season 3. Available at:

Addictive and over-stimulating foods and beverages

These are foods substances which can be overly stimulating to the nervous system, and often can be addictive, such as refined carbohydrates

The ‘food addiction hypothesis’ shows that consuming “addictive foods can cause alterations in neurochemistry – especially dopamine, endogenous opioids and structural changes in the brain. Addictive foods have also been implicated in causing binge-eating disorder Smith, D. and Robbins, T. (2013). The neurobiological underpinnings of obesity and binge eating: a rationale for adopting the food addiction model. [online] Biological Psychiatry, 73 (9), pp. 804–810. Available at: [accessed 25 Aug. 2017]..

Long term consumption can result in:

  • Anxiety
  • Insomnia
  • Hyperactivity
  • Depression
  • Exhaustion and lethargy
  • Cognitive issues

Common stimulants with addictive properties include:

  • Refined sugar
  • Caffeine
  • Chocolate
  • Alcohol
  • Nicotine

Sugar, caffeine, alcohol and nicotine may provide temporary feelings of relaxation and/or energy, but are addictive (particularly when consumed in excess), and over the long term can contribute to anxiety, headaches and insomnia Holt, S. and MacDonald, I. (2011). Depression: Natural Remedies That Really Work. N.Z: Wairau Press, p. 157..

Sugar can act as a stimulant, giving a boost of energy and a burst of serotonin. However the consumption of sugar can also be addictive, can cause blood sugar imbalances, mood swings, anxiety, concentration and attention issues, etc.

In the UK, together we eat 4 million kilos of sugar and 2 million kilos of chocolate every week Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p. 4..

Types of sugar

  • Refined sugar
    • Added to coffee, tea, in yoghurt, over fruit, cereal etc.
    • Found in sugar-rich foods and beverages such as biscuits, pastries, confectionery, sodas, culinary sauces
    • Read the label and watch out for hidden sugars, particularly in pasta, breads, sauces and drinks sweetened with refined sugar
  • “Healthier” sugars
    • Maple syrup
    • Molasses
    • Honey
    • Unconcentrated fruit juices
    • Stevia
      • A natural plant-based sweetener, but which can still trick your body into craving more sugar
    • Sugar alcohols
      • Xylitol
  • Products made from refined flour
    • White pasta
    • Pizza
    • White bread
    • Bagels
    • Rolls
    • Wraps
  • Artificial sweeteners
    • Aspartame
    • Sucralose
    • Saccharin
    • Erythritol
    • Sorbitol
    • Maltitol

Consuming refined sugar, even just from one can of soda, has been shown to cause the following mental health symptoms, especially in children:

  • Difficulties in concentration and attention
  • Irritability
  • Depression
  • Aggression
  • Anxiety

Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p. 19.

Regular sugar consumption has been shown to correlate with the following issues:

  • Lower IQ
  • Aggression
  • Anxiety
  • Hyperactivity
  • Attention deficit
  • Depression
  • Eating disorders
  • Lethargy and fatigue
  • Learning difficulties
  • Mood swings

Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p.88.

Sugar can cause nutritional deficiencies:

  • Sugar contains no nutrients, but merely provides us with a short term burst of energy
    • 90% of the vitamins and minerals have been removed through processing Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p.19.
    • Consuming refined sugar causes magnesium to be lost through the urine Gottfried, S. (2013). The Hormone Cure. New York, NY: Scribner, p. 147.
    • Refined sugar causes a depletion in chromium, which ironically is essential to balancing blood sugar Amen, D. (2013). Unleash The Power Of The Female Brain. New York: Harmony Books, p. 134.
  • Sugar depletes the body’s stores of vitamins and minerals, especially B vitamins, which are essential for mental health

Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p.87.

Sugar sensitivity

If you have sugar sensitivity, you will be more susceptible to sugars in your food and beverages.

Symptoms of sugar sensitivity related to mental health include:

  • Depression
  • Anxiety
  • Being easily stressed
  • Anger and irritability
  • Cravings/addiction for sugary food

DesMaisons, K. (2004). Little Sugar Addicts: End the Mood Swings, Meltdowns, Tantrums, and Low Self-Esteem in Your Child Today. New York: Three Rivers Press, p. 28., Talbott, S. (2007). The Cortisol Connection. Alameda, CA: Hunter House, p. 51.

People with sugar sensitivity tend to have low base levels of the neurotransmitter serotonin, and low beta-endorphins. They tend to crave sugar to make themselves feel better, because the consumption of sugar has the following neurochemical effects:

  • Increases dopamine, the pleasure and motivation neurotransmitter, and therefore can be addictive
  • High blood sugar can help the absorption of tryptophan and its conversation to serotonin
  • Increases endorphins in the brain, particularly in the nucleus accumbens (referred to as the hedonic “hot spot”)

Fortuna, J. (2012). The obesity epidemic and food addiction: clinical similarities to drug dependence. [online] Journal of Psychoactive Drugs, 44 (1), pp. 56–63. Available at: [accessed 24 Aug. 2017].

Effects of sugar consumption on the brain and moods include:

  • Consuming sugar can make you temporarily feel high, feel good
  • Consuming sugar can temporarily give you better impulse control
    • Controlled activities that rely on executive functions (such as attention, reasoning, planning, self control) which override urges, emotions and automatic responses
    • Executive functions, unlike other cognitive functions, seem highly susceptible to glucose fluctuations
    • Evidence shows that self-control failure may be more likely when glucose is low, or glucose transport to the brain from the body is low
    • Some studies have linked criminal behaviour to decreased glucose processing in the brain Gailliot, M., Baumeister, R., DeWall, C., Maner, J., Plant, E., Tice, D., Brewer, L. and Schmeichel, B. (2007). Self-control relies on glucose as a limited energy source: willpower is more than a metaphor. [online] Journal of Personality and Social Psychology, 92 (2), pp. 325-36. Available at: [accessed 24 Aug. 2017].
    • Self-control relies on glucose as a limited energy source: willpower is more than a metaphor Gailliot, M., Baumeister, R., DeWall, C., Maner, J., Plant, E., Tice, D., Brewer, L. and Schmeichel, B. (2007). Self-control relies on glucose as a limited energy source: willpower is more than a metaphor. [online] Journal of Personality and Social Psychology, 92 (2), pp. 325-36. Available at: [accessed 24 Aug. 2017].
  • Consuming sugar can make you temporarily feel less sensitive to pain DesMaisons, K. (2004). Little Sugar Addicts: End the Mood Swings, Meltdowns, Tantrums, and Low Self-Esteem in Your Child Today. New York: Three Rivers Press, p. 21.
  • However, after a sugar high, your body compensates by removing sugar from the blood, resulting in a crash in blood sugar and a crash in serotonin and beta endorphins which then can make you feel down DesMaisons, K. (2004). Little Sugar Addicts: End the Mood Swings, Meltdowns, Tantrums, and Low Self-Esteem in Your Child Today. New York: Three Rivers Press, p. 19.

Caffeine can be over-stimulating particularly to people who are very sensitive to it, and can contribute to sleep issues, anxiety, hyperactivity, attention and concentration deficits.

Caffeine can increase serum lactate and can deplete serotonin and melatonin, aggravate the symptoms of PMS, deplete B and C vitamins, potassium, magnesium, calcium and zinc, all of which can contribute to anxiety and insomnia.Scott, Trudy (2011), The Anti-Anxiety Food Solution: How the Foods You Eat Can Help You Calm Your Anxious Mind, Improve Your Mood and End Cravings”. Oakland, CA: New Harbinger Publications

In the UK, together we drink 1.5 billion caffeinated drinks per week (including coffee, tea and cola) Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p. 4..

In the US, 85% of Americans consume at least 1 caffeinated beverage per day with average daily consumption of 1.8 drinks Mitchell, D., Knight, C., Hockenberry, J., Teplansky, R. and Hartman, T. (2014). Beverage caffeine intakes in the US. [online] Food and Chemical Toxicology, 63, pp. 136–42. Available at: [accessed 25 Aug. 2017]..

Caffeine is contained in varying amounts in:

  • Coffee
  • Tea
  • Sodas such as coke
  • Chocolate

Of these, the only ones to categorically avoid are sodas, as they have no nutritional value and are full of sugars and chemicals. Coffee, tea and dark chocolate however, can contain a multitude of polyphenols and phytochemicals which, in moderation, can be beneficial to mental health.

You have to be the judge how caffeine affects you, and whether you need to avoid it altogether, or maybe just reduce the quantities you consume.

Caffeine does however have harmful effects on the development of the brain of the foetus which is why it is contraindicated in pregnancy. The defects seen include anencephaly (being born without a brain, or lesser types of brain deformity). It is also believed to damage the serotonin system in the developing foetus Li, X.-D., He, R., Qin, Y., Tsoi, B., Li, Y., Ma, Z., Yang, X. and Kurihara, H. (2012). Caffeine interferes embryonic development through over-stimulating serotonergic system in chicken embryo. [online] Food and Chemical Toxicology, 50 (6), pp. 1848–53. Available at: [accessed 25 Aug. 2017]..

In the UK, we drink 120 million alcoholic drinks per week together Holford, P. (2004). Patrick Holford’s New Optimum Nutrition Bible. London: Piatkus, p. 4..

The US fares better than the UK in terms of alcohol consumption:

  • 30% do not drink, another 30% consume less than 1 drink/week
  • The highest 10% consume 74 million drinks/week

World Health Organization. (2014). Global Status Report on Alcohol and Health. [online] Luxembourg: World Health Organization. Available at: [accessed 25 Aug. 2017].

Alcohol can be detrimental to mental health:

  • Alcohol lowers executive brain function Amen, D. (2013). Unleash The Power Of The Female Brain. New York: Harmony Books, p. 22.
  • Alcohol raises cortisol, the stress hormone
  • Even one glass of wine can impact your sleep, reducing the amount of restorative deep and REM sleep you get
  • Alcohol can disrupts hormone balance and exacerbate symptoms of PMS in females
  • Alcohol can cause nutritional deficiencies (zinc, magnesium, B vitamins, vit c, EFA, antioxidants)Scott, Trudy (2011), The Anti-Anxiety Food Solution: How the Foods You Eat Can Help You Calm Your Anxious Mind, Improve Your Mood and End Cravings”. Oakland, CA: New Harbinger Publications
  • Alcohol can negatively impact the metabolism of tryptophan which is essential for serotonin production
  • Alcohol can contribute to reactive hypoglycemia
  • Alcohol can damage the gut

As with certain caffeine containing beverages, certain alcoholic beverages have health benefits which can offset the presence of alcohol, but only in small doses. For instance a glass of red wine contains a number of polyphenols, phytochemicals, and antioxidants such as resveratrol.