8 ways to improve your gut health

Many of us are advised to ‘trust our gut’, meaning don’t be dismissive of our gut instincts, but how many of us actually know what our gut is in the biological sense, why it’s so important and how to keep it healthy? In this article, we’ll get you familiar with your gut, specifically your gut microbiome, and shed light on how you can improve your gut health naturally, so let’s dive in…

Meet your gut!

The gastrointestinal tract, commonly known as the gut, is the long tube that begins at your mouth and ends in your bottom at your anus. It’s a bit like a train route that the food you eat travels on with lots of stops at different stations along the way. These stops include the oesophagus, stomach, small intestine, large intestine, and rectum.

Now meet your gut microbiome!

Meanwhile, “microbiome” refers to the collection of trillions of microbes such as bacteria, fungi and viruses that live in the human body in harmony, in balance and with a purpose; an ecosystem just like the Amazon rainforest. This is known as the “human microbiome”, which is completely unique for each individual.

There are many microbiomes in different areas of the body, such as the skin microbiome, the uterus microbiome and the vaginal microbiome, to name just a few. In fact, amazingly, over half your body is made up of microbes! This article will focus on the gut microbiome. The majority of the microbes in your gut can be found in the pouch shaped section of your large intestine called the caecum.

Why is it important to improve gut health?

Your gut microbiome affects your digestion, immune system, mood, and cognitive function, protecting us from pathogens (bugs that can induce disease), and assisting us in accessing nutrients and energy from food. For example, did you know that up to 80% of your immune system is in your gut? So, if there are imbalances in your gut, there’s likely to be disruption to the effectiveness of your immune system, which could leave you more prone to infection and disease.

Those clever microbes in your gut helpfully digest the soluble fibre from the food you eat transforming it into metabolites, such as short-chain fatty acids (SCFAs). These metabolites are essential for a variety of things, spanning gut health, blood sugar, appetite, fats in the blood, such as cholesterol control, and the immune system.

Vital vitamin production

That’s not all your smart gut microbes get up to; they also digest protein and make B vitamins and vitamin K2. This is essential as our body lacks the enzymes (proteins) to create vitamin B12 and vitamin K; in fact it has been estimated that up to half of the vitamin K we need each day is produced by our gut bacteria.

The eight B vitamins have a range of vital functions in the body impacting your energy levels, brain function, and cell metabolism. They’re instrumental in releasing energy from carbohydrates and fat, breaking down amino acids and moving oxygen and energy-containing nutrients around the body.

Vitamin K meanwhile, is needed for blood clotting, helping wounds to heal and may even contribute to keeping your bones healthy. So, if we don’t have a good balance of the beneficial bacteria, this can affect our vitamin levels, which can, in turn, disrupt these functions.

A balanced gut is a happy gut

Safe to say, looking after your gut microbiome strongly benefits your overall health. There’s still much to learn, but researchers agree a healthy gut, like a healthy rainforest, is one with high diversity. Diversity of microbial species is critically important to balance. Lower diversity in your microbiome is considered to be a sign of dysbiosis – an imbalance in your gut.

However, it isn’t just lack of microbial diversity; an overgrowth of inflammation-promoting species of microbes can be a sign of dysbiosis too, as can an overgrowth of bacteria in the small intestines, as we see in Small Intestinal Bacterial Overgrowth (SIBO). In some studies, it’s been reported that between 43-78% of people with irritable bowel syndrome symptoms have SIBO. An unbalanced microbiome is likely to struggle to protect against pathogenic organisms. This may lead to inflammation that has been linked to the development of several diseases.

Low microbial diversity has been seen in people with a variety of health conditions such as, inflammatory bowel disease, psoriatic arthritis, type 1 and 2 diabetes, atopic eczema, coeliac disease, autoimmune diseases, obesity arterial stiffness and cardiometabolic conditions (think heart attack, stroke, diabetes, insulin resistance and non-alcoholic fatty liver disease). An imbalance in the gut microbiome may also have a role in the development of colorectal cancer. We’re still learning about the details of this relationship between the diversity of the gut and these conditions.

Did you know you can disrupt your gut?

There are many things that can disrupt this harmony of microbial balance and diversity in your gut microbiome. Recognising what can disrupt the happy medium can be helpful in restoring your gut health.

8 ways to improve your gut health

Now that you’re acquainted with your gut, here are some simple things you might like to do to support your gut health.

1) 30+ plant foods a week

You usually get out of your body what you put in, so it’s no surprise that diet has the largest impact on the gut microbiome. Eating a diverse diet that’s high in dietary fibre (from plant foods) will support a healthy gut microbiome. Vegetables (broccoli, carrots), legumes (peas, beans and pulses), nuts, and seeds, fruits (berries, pears), wholegrains (oats, barley, rye), and herbs and spices (turmeric, cinnamon) are all rich in soluble fibre.

Why does a diet rich in plant fibres do your gut so many favours? It’s down to the relationship between prebiotics, probiotics and postbiotics, which sound similar but have different roles. Put simply, prebiotics, mostly found in dietary fibre, serve as “food” for probiotics (the gut microbes that make up your gut microbiome). Once fuelled by prebiotics, all these lovely friendly bugs produce postbiotics as a result of their activity in your gut, which includes fermentation.

The wonders of SCFAs

Short Chain Fatty Acids (SCFAs) are an example of a postbiotic that results from gut microbes digesting their prebiotic “food” from dietary fibre you’ve eaten and fermenting that fibre. Far from being a waste product of probiotics, postbiotics such as SCFAs have been credited with many health benefits, including reducing disease, providing fuel for the cells lining your intestines, which act like bouncers, controlling what comes in and out, as well as exerting anti-inflammatory effects. Amongst other things, the gut barrier integrity is essential to avoid some pathogenic bacteria entering into the bloodstream and reaching different tissues.

The American Gut Project found that people who eat more than 30 different plant-based foods a week tend to have far greater microbial diversity and SCFA producing bacteria. People who eat more than 30 different plant-based foods a week were also found to have significantly fewer antibiotic resistant genes contained in their stool than those who eat 10 or fewer plant-based foods per week.

With antibiotics known to disrupt the gut by killing the beneficial, as well as unbeneficial, bacteria in your gut microbiome, leading to lower microbial diversity, one way to raise your gut’s diversity levels again is to make sure you’re including a wide array of plant-based foods in your diet each week.

Tuck into soluble fibre

Fibre can be split into two broad categories: insoluble and soluble. Whilst insoluble fibre travels untouched through our digestive system, soluble fibre is broken down in our large intestine and acts as a prebiotic, feeding those microbes in your gut, and therefore encouraging a healthy gut. Just as different animals eat various foods, each microbe has its preferred food source, from veg and fruit, to wholegrains, pulses, and nuts, contain a different blend of fibre. This underlines the importance of having a diverse range of plant-based food in your diet for a good gut health.

Try this…

Our handy checklist of plant-based foods can be great at helping you see if you can tick off 30 or more different ones each week. Why not stick it on your fridge or have it in your kitchen as a useful reminder when you plan your meals and shopping list for the following week?

You can print and download our handy plant-based foods checklist by clicking the button below.

When it comes to these conditions, without microbiome testing, understanding what’s best for you involves a certain amount of guesswork. Identifying your triggers is key here so that you get to know your body and how it responds to different foods, rather than just deciding to avoid certain plant foods completely. Making the connection between what you eat and the onset of symptoms can be helped using a food app like myfood24 or MyFitnessPal. 

Some people, such as those with inflammation in their gut, have problems when they eat foods containing the indigestible (insoluble) fibre part. Rather than cut out these foods entirely (and all the vital nutrients they contain) you could see if the following makes a difference:

1. Making sure you cook your veggies rather than eating them raw.
2. Peeling the skin off veggies that you decide to enjoy with your meals.
3. Removing the seeds of veggies you add to your dishes.
4. Soaking beans, seeds, nuts (especially peanuts). Aim for overnight soaking in water for beans and peanuts; some nuts and seeds require less time, for example 20 mins to four hours.

2) Eat fermented foods daily

Fermentation is a process which sees microbes in your gut break down sugars, helping to extract nutrients and energy from food. Fermented foods contain live microbes (those lovely friendly bugs!)

Including fermented foods, also known as probiotic foods, in your diet is a win for good gut health as it increases the number of beneficial microbes in your gut microbiome, leading to a happier gut with greater diversity. The probiotic-packed fermented probiotic foods that are likely to have a beneficial impact on health and the gut microbiome include:

• yoghurt
• kefir
• sauerkraut
• kimchi
• miso
• kombucha – though keep this to 1-2 drinks a week due to the sugar content.

3) Get plenty of polyphenols

Polyphenols, compounds found in plant foods like wine, tea, apples, raw cacao (the raw unprocessed form of cocoa), coffee, berries and extra virgin olive oil, may help improve your gut health.

Microbes in our gut help us metabolise these compounds and they positively impact the composition of the gut microbiome. The metabolites that result from gut microbes metabolising polyphenols can help control the gut microbiome’s composition. For example, they promote the growth of beneficial bacteria and limit the growth of pathogens.

The polyphenol metabolites may also affect brain biochemistry by acting as neurotransmitters – chemical substances released by neurons to signal an affect to another cell in the body – in your central nervous system.

Polyphenols increase the abundance of a beneficial bacteria called Akkermansia muciniphila too, which is involved in obesity, glucose metabolism, and intestinal immunity.

Try this…

Why not finish your balanced meal with some juicy berries or an apple? You could also give cooking with extra virgin olive oil a whirl – it often appears in the Mediterranean diet, which seems to be one of the most beneficial diets in regards to heart health and lifestyle diseases, such as type 2 diabetes and even some forms of cancer.

4) Move your body

Aside from diet, exercise is another great way to restore your gut health.

Getting active has been shown to alter the gut microbiome in a favourable way independent of diet, though these changes may depend on obesity status of a person and the type and intensity of the exercise being done. For example, exercise has independent effects on the gut microbiota, but longer duration or higher intensity aerobic training (which typically includes activities like walking, jogging, indoor cycling, and aerobic dancing) may be required to bring about significant changes to the gut microbiome.

For some inspiration, you could give HIIT (high-intensity interval training) a whirl – with this type of workout being as short as 20-30 minutes, you can easily slot it into your daily routine.

5) Puppy love

Although more studies are needed on adults, growing research shows that farmyard animals, cats, dogs and other furry animals seem to have a beneficial affect on the gut microbiomes of those they live with, especially on young children.

In an albeit small study of 24 healthy, full-term infants, microbial richness and diversity of stool samples were higher in infants living with pets or a pet. Indeed, studies have revealed an increased abundance of beneficial bacteria strains in the gut microbiomes of three- and four-month-olds thanks to furry pets. Pet exposure was associated with a significant enrichment of Oscillospira and Ruminococcus in stool samples of three-month-olds. Both these bacteria types are negatively associated with a tendency to develop allergies and obesity.

Prolonged long-term exposure to stables until the age of five years was associated with the lowest frequencies of asthma, hay fever, and allergies. Indeed, studies have found early-life exposure to pets and siblings may give infants protection against allergic disease, whilst growing up on farms may give protection against asthma. The microbiome may be one way by which this protection against allergy is produced.

Pinpointing the specific gut microbes and mechanisms responsible for the association between animal exposure and low allergy rates could possibly pave the way for the development of potential strategies to target the prevention and treatment of allergic disorders. As it stands though, having a furry friend around could help your little ones’ immunity.

6) Prioritise your sleep

Emerging research suggests that sleep deprivation can lead to changes in microbiome composition. A 2013 study found that total microbiome diversity in males was positively correlated with increased sleep efficiency and total sleep time, and was negatively correlated with waking up during the night after falling asleep.

If you’re struggling to sleep, find out what might be getting in the way. Our fifteen steps to better sleep picks up on some common ways to improve your overall sleep quality and time. Aiming for seven-nine hours sleep if you’re aged 18-64 or seven-eight hours if you’re over 65 is likely to promote gut microbiome diversity.

7) Make time for yourself

Stress can reshape the gut microbiome’s composition, with negative consequences. Whilst, minimising stress might feel easier said than done, it can be useful to notice and acknowledge the stress you might be experiencing. Simply knowing that the stress you may be experiencing will pass at some point and that there will be more calming times, however fleeting, without you doing anything different, can be comforting. Look out for those moments amidst the stress so you start to spot them for yourself.

It can also be helpful to take time to relax and unwind when you can and prioritise the things you enjoy. You might find our article on how to feel happier helpful.

8) Buy organic where possible

Modern farming often involves using synthetic fertilisers and chemical pesticides to grow more produce, with pesticides destroying insects or other organisms harmful to farmed plants or to animals. Pesticides used in agriculture can often leave detectable traces of chemicals in, or on, our food known as ‘residues’. Exposure to pesticides and chemicals can disrupt our gut microbiome.

Although we can’t completely avoid chemical consumption and pesticide exposure, where possible, we can opt for organic foods, which use ecologically-based pest controls and biological fertilisers mainly from animal and plant wastes.

Foods that contain less pesticide residue

If you’re not able to always buy organic food, why not try and incorporate some tasty foods into your diet that boast less pesticide residue levels in comparison to other fruit and veg? These include:

• sweetcorn
• onion
• cabbage
• asparagus
• avocados
• pineapples
• mangos
• honeydew melons?

UK charity Pesticide Action Network (PAN) helpfully analyses government data and has turned it into the “Dirty Dozen”, a handy list of produce that have recorded the highest levels of pesticides residue. At the time of writing, the top five on their list were:

1. grapefruit
2. soft citrus – clementines, mandarins, satsumas etc
3. strawberries
4. oranges
5. dried grapes (sultanas, raisins)

Can you guess what the other seven foods are? Head over to their website to find out.

Try this…

You can stick this on your fridge or in your back pocket when you go food shopping and use it to inform you of which foods you could aim to buy the organic versions of (check the labels), so even if a completely organic food shop is out of the question, you know where to try and focus.

Bonus tip: Intermittent fasting may improve your gut health

Time-restricted fasting is where you only eat during certain hours of the day and refrain from eating during the remaining hours.

Each night, cell repair and replication in your gut lining is stimulated to maintain gut integrity. Although most research has mainly been carried out in animal studies so far, experts speculate that prolonged nightly fasting (keeping your food intake to the typical 12 daylight hours only) may result in improvements in human health, reducing the risk of several common chronic diseases.

Some people practice different timings but a great starting point is 12/12 – that is, eating all your food intake each day in a 12 hour window and fasting for the other 12 hours. If you’re sleeping for seven-nine hours of those hours, 12 it isn’t much time without food! Plus, giving yourself more time to digest between your last meal and switching off the light can help you reach the 12 hour fasting mark. Why not give it a try for a week or so and see how you feel in the mornings, some people find they wake feeling refreshed and raring to go. Do you notice a difference?

So, there are small but impactful lifestyle changes you can make for a happy, healthy gut microbiome. Gradually making healthy swaps makes it seem less daunting. It might work well to focus on one of the changes discussed above, such as exercise, then the following week make some dietary changes, and the following week concentrate on prioritising your sleep. Which one do you fancy putting into action first?

Reviewed by:

Dr Brian Fisher MBBch MBE MSc FRSA – Clinical Director

Nicky Verity MSc BSc – Wellbeing Researcher

References

1. Azad MB, Konya T, Maughan H, et al. (2013) Infant gut microbiota and the hygiene hypothesis of allergic disease: impact of household pets and siblings on microbiota composition and diversity. Allergy, Asthma & Clinical Immunology 9: 15 (doi: 10.1186/1710-1492-9-15).
2. Blaak EE, Canfora EE, Theis S, et al. (2020). Short chain fatty acids in human gut and metabolic health. Benef Microbes. 11: 411-455 (doi: 10.3920/BM2020.0057)
3. Braverman, J and Corleone J (2019) List of Foods High in Soluble Fiber. Live strong
4. Chaix A, Manoogian ENC, Melkani GC, et al. (2019) Time-Restricted Eating to Prevent and Manage Chronic Metabolic Diseases. Annu Rev Nutr. 39: 291-315 (doi: 10.1146/annurev-nutr-082018-124320).
5. Chiu K, Warner G, Nowak RA, et al. (2020) The Impact of Environmental Chemicals on the Gut Microbiome. Toxicological Sciences 176 : 253–284 (doi: 10.1093/toxsci/kfaa065).
6. Cunningham D (n.d.) Q&A Microbiome. The Royal Marsden NHS Foundation Trust
7. DeGruttola AK, Low D, Mizoguchi A, et al. Current Understanding of Dysbiosis in Disease in Human and Animal Models. Inflamm Bowel Dis. 22:1137-50 (doi: 10.1097/MIB.0000000000000750. PMID: 27070911).
8. Deng F, Li Y and Zhao J (2019). The gut microbiome of healthy long-living people. Aging (Albany NY) 11: 289-290. (doi: 10.18632/aging.101771).
9. Dernini S, Berry E, Serra-Majem L, et al. (2017) Med Diet 4.0: The Mediterranean diet with four sustainable benefits. Public Health Nutrition 20: 1322-1330 (doi:10.1017/S1368980016003177).
10. Dong TS and Gupta A (2019) Influence of Early Life, Diet, and the Environment on the Microbiome. Clinical Gastroenterology and Hepatology 17: 231-242 (dpi: 10.1016/j.cgh.2018.08.067).
11. Environmental Working Group (EWG) Science Team (2023) EWG’s 2023 Shopper’s Guide to Pesticides in Produce. Environmental Working Group (EWG).
12. Filosa S, Di Meo F, Crispi S. (2018) Polyphenols-gut microbiota interplay and brain neuromodulation. Neural Regen Res. 13: 2055-2059. (doi: 10.4103/1673-5374.241429)
13. Francino MP (2016) Antibiotics and the Human Gut Microbiome: Dysbioses and Accumulation of Resistances. Frontiers in Microbiology 6: 237ra265 (doi: 10.3389/fmicb.2015.01543)
14. Gallaghar J (2018) More than half your body is not human. BBC
15. Harvard T.H. Chan School of Public Health (n.d.) The Nutrition Source. Harvard T.H. Chan School of Public Health.
16. Henderson R and Bonsall A (n.d.) The digestive system. Patient
17. Hill MJ (1997) Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev. Suppl 1: S43-5 (doi: 10.1097/00008469-199703001-00009).
18. Horby J (2016) How to make sauerkraut. BBC Good Food.
19. Johnston A (n.d) Kombucha. BBC Good Food.
20. Kim H, Sitarik AR, Woodcroft K, et al. (2019) Birth Mode, Breastfeeding, Pet Exposure, and Antibiotic Use: Associations With the Gut Microbiome and Sensitization in Children. Curr Allergy Asthma Rep.19: 22 (doi: 10.1007/s11882-019-0851-9).
21. Kirjavainen PV, Karvonen AM, Adams RI et al. (2019) Farm-like indoor microbiota in non-farm homes protects children from asthma development. Nat Med 25:1089–1095. (doi: 10.1007/s11882-019-0851-9).
22. Krajmalnik-Brown R, Ilhan ZE, Kang DW, et al. (2012) Effects of Gut Microbes on Nutrient Absorption and Energy Regulation. Nutr Clin Pract. 27: 201-14 (doi: 10.1177/0884533611436116).
23. Leeuwendaal NK, Stanton C, O’Toole P, et al. (2022) Fermented Foods, Health and the Gut Microbiome. Nutrients 14: 1527 (doi: 10.3390/nu14071527).
24. Li AL, Ni WW, Zhang QM, et al. (2020) Effect of cinnamon essential oil on gut microbiota in the mouse model of dextran sodium sulfate-induced colitis. Microbiol Immunol. 64: 23-32 (doi: 10.1111/1348-0421.12749).
25. Li HY, Zhou DD, Gan RY, et al. Effects and Mechanisms of Probiotics, Prebiotics, Synbiotics, and Postbiotics on Metabolic Diseases Targeting Gut Microbiota: A Narrative Review. Nutrients. 13: 3211 (doi: 10.3390/nu13093211).
26. Madison A, Kiecolt-Glaser JK (2019) Stress, depression, diet, and the gut microbiota: human-bacteria interactions at the core of psychoneuroimmunology and nutrition. Curr Opin Behav Sci. 28: 105-110 (doi: 10.1016/j.cobeha.2019.01.011).
27. Maier RM, Palmer MW, Andersen GL, et al. (2010) Environmental Determinants of and Impact on Childhood Asthma by the Bacterial Community in Household Dust. Applied and Environmental Microbiology 76: 2663 – 2667. (doi: 10.1128/AEM.01665-09).
28. Mailing LJ, Allen, JM, Buford TW, et al. 2019. Exercise and the Gut Microbiome: A Review of the Evidence, Potential Mechanisms, and Implications for Human Health. Exerc. Sport Sci. Rev. 47: 75–85 (doi: 10.1249/JES.0000000000000183)
29. McDonald D, Hyde E, Debelius JW et al. (2018) American Gut: an Open Platform for Citizen Science Microbiome Research. Host-Microbe Biology 3: e00031-18 (doi: 10.1128/mSystems.00031-18).
30. Morowitz MJ, Carlisle EM and Alverdy JC (2011) Contributions of intestinal bacteria to nutrition and metabolism in the critically ill. Surg Clin North Am. 91: 771-85, viii. (doi: 10.1016/j.suc.2011.05.001).
31. Naito Y, Uchiyama K and Takagi T (2018) A next-generation beneficial microbe: Akkermansia muciniphila. J Clin Biochem Nutr. 63: 33-35 (doi: 10.3164/jcbn.18-57)
32. Naito Y, Uchiyama K and Takagi T (2018) A next-generation of beneficial Microbe: Akkermansia muciniphila. J Clin. Biochem. Nutr. 63: 33-35 (doi: 10.3164/jcbn.18-57).
33. NHS (2020) Vitamin K. NHS
34. NHS, 2021. What is IBS? NHS.
35. Nogal A, Valdes AM, Menni C (2021) The role of short-chain fatty acids in the interplay between gut microbiota and diet in cardio-metabolic health. Gut Microbes: 13: 1-24. (doi: 10.1080/19490976.2021.1897212)
36. Patterson RE and Sears DD (2017) Metabolic Effects of Intermittent Fasting. Annual Review of Nutrition 37: 371-393 (doi:10.1146/annurev-nutr-071816-064634).
37. Pesticide Action Network UK (n.d.) The Dirty Dozen. Pesticide Action Network UK.
38. Peterson CT, Rodionov DA, Iablokov SN, et al. (2019) Prebiotic Potential of Culinary Spices Used to Support Digestion and Bioabsorption. Evidence-Based Complementary and Alternative Medicine 2019: Article ID 8973704 (doi: 10.1155/2019/8973704).
39. Riedler J, Braun-Fahrländer C, Eder W, et al. (2001) Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey. Lancet 358:1129-33 (doi: 10.1016/S0140-6736(01)06252-3).
40. Ríos-CoviánD, Ruas-Madiedo P, Margolles A, et al. 2016. Intestinal Short Chain Fatty Acids and their Link wtih Diet and Human Health. Front. Microbiol.(doi: 10.3389/fmicb.2016.00185).
41. Singh A and Suni E (2022) How Much Sleep Do We Really Need? Sleep Foundation.
42. Smith RP, Easson C, Lyle SM, et al. (2019) Gut microbiome diversity is associated with sleep physiology in humans. PLOS ONE The Microbiome Across Biological Systems 14: e0222394 (doi: 10.1371/journal.pone.0222394).
43. Tun HM, Konya T, Takaro T, et al. Exposure to household furry pets influences the gut microbiota of infant at 3-4 months following various birth scenarios. Microbiome 5: 40 (doi: 10.1186/s40168-017-0254-x).
44. Valdes AM, Walter J, Segal E, et al. Spector TD (2018) Role of the gut microbiota in nutrition and health. BMJ. 361: k2179 (doi: 10.1136/bmj.k2179).
45. Venegas DP, De la Fuente M, Landskron G, et al. 2019. Short Chain Fatty Acids (SCFAs)- Mediated Gut Epithelial and Immune Regulation and Its Relevance for Inflammatory Bowel Disease. Front. Immunol. (doi: 10.3389/fimmu.2019.00277).
46. Wiertsema SP, van Bergenhenegouwen J, Garssen J, et al. (2021) The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients 13: 886 (doi: 10.3390/nu13030886).
47. Wright, C.P., Dooley, M.T., & Leeson, H. (2021). Eradication of small intestinal bacterial overgrowth in irritable bowel syndrome using herbal therapy: A case report. International Journal of Functional Nutrition, 2, 13. https://doi.org/10.3892/ijfn.2021.23.
48. Xu Z and Knight R (2015). Dietary effects on human gut microbiome diversity. British Journal of Nutrition, 113: S1-S5 (doi:10.1017/S0007114514004127).