By Michaela Carrick, BSc Human Nutrition & Laura Reilly, MSc Nutrition, Food and Health
What is the Gut Microbiome?
The human microbiota consists of trillions of microbial cells (including bacteria, fungi and yeasts). These microbes, along with their genes, are collectively known as the gut microbiome.
The gut microbiome plays an important role in our health; (for example they regulate our immune system, help to digest food, and help the body to make vitamins like B2, B6, B12 and K).
A healthy microbiome is one with a large and diverse collection of microbes. In general, the more of these tiny bugs you have, the better.
Diet Counts
What we eat has a huge influence on our microbiome. Eating a diverse diet with lots of variety is the best way to make sure our microbiome is healthy.
When it comes to choice of diet, plant based diets have been shown to be particularly good for gut health. These are usually high in fibre, and contain prebiotic fibres. Diets containing prebiotics favour the growth of beneficial gut bacteria. Prebiotics are found in garlic, onions, leek, dates, nectarines, dried mango, watermelon, beetroot, artichoke, asparagus, pistachios, cashews, chickpeas and other beans.
So how many plant foods should we be eating for a healthy microbiome?
The American Gut Project was a huge study that analysed the diet and microbiome of over 10000 people. They discovered that people who ate 30+ plant foods a week had a more diverse gut microbiome than people who ate 10 or less. (1)
Trying to eat ≥30 plant foods a day can sound daunting but it isn’t as difficult as it sounds. You can build up your total by trying a new plant based food each day.
Here are some tips to help you reach that 30 mark
- Make sure half of your plate is vegetables. Choose a variety of different types and colours (e.g lots of leafy greens, beetroot, tomato, sweetcorn, roasted squash, grated or sliced carrot, peppers and onions of different colours).
- Add mixed beans to meals such as salads, bolognaise, chili con carne.
- Add nuts and /or seeds to salads, smoothies and meals. Or just enjoy them as a snack.
- Add fruit and/or vegetables to breakfast dishes (e.g mushrooms or spinach with eggs, sliced pear with porridge).
- If you don’t already, include 2 or 3 plant based meals in your weekly meal plans. You could try a sweet potato and lentil curry, roasted vegetable pasta with cheese, or even beans on toast.
- Snack on roasted chickpeas, edamame beans or veggie sticks (e.g carrot).
- Mix fruit or vegetables (e.g kale, cucumber, beetroot) into your morning smoothie.
- Choose fruit based desserts and cakes/slices (e.g a colourful fruit salad and yoghurt, fruit loaf or carrot cake).
- Choose whole grain breads/cereals (e.g start the day with oats, add chia or flax seeds, add quinoa to your salads, barley/brown rice with main meals).
- Pop vegetables into your usual dishes (e.g grate carrot and courgettes into meatloaf, meatballs and other mince dishes, add cauliflower or butter beans to chicken curry).
- Serve meals with a side salad of mixed vegetables (e.g lettuce, spinach, red onion, tomatoes, cucumber, and different-coloured peppers) or a side of roast vegetables (e.g carrots, parsnips, and sweet potatoes).
Fermented foods
Some research has suggested that people who eat fermented foods (such as live yoghurt, Kefir, kimchi, sauerkraut, kombucha, and the Lockdown favourite – sourdough! ) have more diverse microbiomes (2). At present, though, we don’t have enough evidence to say for sure. If you would like to try fermented foods, however, you can find them in many supermarkets. You could start by trying a daily yoghurt with ‘live cultures’.
References
1. McDonald D, Hyde E, Debelius JW, Morton JT, Gonzalez A, Ackermann G, Aksenov AA, Behsaz B, Brennan C, Chen Y, DeRight Goldasich L. American Gut: an open platform for citizen science microbiome research. Msystems. 2018 May 15;3(3):e00031-18.
2. Singh RK, Chang HW, Yan DI, Lee KM, Ucmak D, Wong K, Abrouk M, Farahnik B, Nakamura M, Zhu TH, Bhutani T. Influence of diet on the gut microbiome and implications for human health. Journal of translational medicine. 2017 Dec;15(1):1-7.
