Science knows it: the human body functions better if it obtains its nourishment and nutrients from as wide a selection of plants as possible. This keeps the microbiome in your gut on top form and enables the digestive tract to do its job thoroughly. The good news: chocolate and coffee count too!
The consuming of 30 different plants a week can promote the diversity and health of your gut microbiome. And that, in turn, can affect many other aspects of your health. If you think that 30 different plants is a bit much, rest assured: it's not just fruit and vegetables that count, but also grains, nuts, seeds, herbs and spices. Just two freshly prepared curries can provide you with a considerable number of the required thirty different plants.
More than just a fad: prebiotics
For years, many studies have indicated that eating 5 portions of fruit and veg a day has a significant positive impact on your long-term health. However, many experts are of the opinion that the variety of plants consumed is just as important. The idea of eating 30 different plants every week is therefore more than just a fad. Eating habits, such as the Mediterranean diet, which contains a large variety of plant-based foods, are closely linked to a lower risk of long-term health problems such as heart disease and type 2 diabetes. However, eating a wide variety of plant-based foods is equally important for the health of the gut microbiome – the community of bacteria and other microorganisms that live in the gut. See the previous article.
Plants contain so-called prebiotics, which serve as food for the intestinal bacteria that are beneficial to us. The prebiotics in plants include various types of fibre and other carbohydrates, as well as chemical substances called polyphenols. Polyphenols are responsible for the colour of many plants and also have antioxidant and anti-inflammatory properties.
Different plants contain different prebiotics, which in turn feed different gut bacteria. This means that eating a wide range of plants is likely to boost the diversity of bacteria in your gut microbiome. And a more diverse microbiome, rich in beneficial bacteria, is associated with a better functioning and more resilient gut.
Why the number 30?
You may have heard that experts such as ZOE co-founder Prof. Tim Spector recommend eating 30 different plants a week. You may also have seen it posed as a challenge on social media. In 2018, scientists published the results of the American Gut Project, a collaboration between researchers and more than 10,000 citizen scientists from the US, UK and Australia. The volunteers provided detailed information about their eating habits. They also gave samples of their stool. The researchers analysed these to find out which intestinal bacteria they contained. And the study found that participants who ate a greater variety of plants had a more diverse gut microbiome. Participants who ate 30 or more different plants per week were more likely to have beneficial gut bacteria than those who ate only 10 plants per week. Their stool samples also contained more healthy chemicals produced by these bacteria.
What counts as a plant?
It doesn't have to be difficult to increase the variety and quantity of plants in your diet, especially if you expand your idea of plant foods to include spices, herbs, nuts and seeds. Moreover, it is not crucial to eat large quantities of each plant to reap the benefits. Small pinches of herbs and spices also count. However, to get the maximum benefits from herbs and spices, try to eat them several times a week. Important: pay attention to the colour of the vegetables you eat. For example, red, green and yellow peppers count as three different plants. That's because different colours mean different polyphenols, which stimulate different types of gut microbes – and each have different health benefits.
There's plenty to choose from – know what
Vegetables come in all shapes, sizes and colours. Your 30 plants can include different types of root vegetables, salad leaves, cruciferous vegetables (also known as brassicas) and allium plants such as onions, garlic and chives.
There is a huge selection of fruits, including those usually associated with savoury dishes, such as tomatoes and avocados. Legumes include beans, pulses and peas. These are incredibly versatile and a great source of fibre. Grains and cereals that count include barley, various types of rice and those that are often made into flour, such as wheat and rye. If possible, opt for whole grains, which provide you with all the fibre the plant has to offer. On the whole, whole grains contain more nutrients than refined grains like white flour and white rice. They are also better for blood sugar and blood fat levels. Nuts and seeds contain protein, fibre, healthy fats, vitamins and minerals. They make excellent snacks and can add a satisfying crunch to many meals. Herbs and spices are a healthy way to add an extra burst of flavour to your meals. Both fresh and dried are suitable.
Surprise – coffee and chocolate also count
You might not expect some foods to be included because they don't look like plant-based foods (or drinks). But healthy versions of these foods all count towards your goal of 30 plants a week:
Coffee: coffee beans are the seeds of the coffee berry and belong to the fruit category. Much of the fibre and many of the polyphenols in ground coffee beans end up in the drink. And coffee has a string of potential health benefits.
Dark chocolate: made from the seeds of a tropical fruit, chocolate contains polyphenols and can be beneficial to health. The healthiest varieties have a high percentage of cocoa solids – 70% or more – and contain no artificial additives.
Popcorn: these corn kernels are a whole-grain product. If popcorn is air-popped and does not contain too much salt or butter, it is considered a healthy snack by the American Heart Association.
More tips to increase the number of plants you consume
Stock up on supplies: just as you should have plenty of fresh fruit and vegetables to hand, your cupboards should be stocked with canned fruit, beans and packets of pulses.
Jazz up salads: nuts or seeds can add a nice crunch to your salads, and apples or fennel can make them more interesting. Herbs add flavour, and legumes or tofu cubes add substance.
Jazz up soya yoghurt: fermented yogurt and kefir are good for the gut. Add nuts, seeds or fruit such as berries to give the yoghurt a whole new flavour.
Beans are welcome: not only can you add them to salads and stews, but you can also make delicious dips with beans or replace meat in recipes with lentils or tofu. Instead of using just one type of bean, try a mixture of two or three varieties.
Add hidden greens: leafy greens like spinach or finely chopped kale wilt quickly when stirred into dals, stews and stir-fries, subtly increasing the plant content of your meal.
Snacks: swap snacks such as potato chips or sweets for mixed nuts, berries or sliced peppers to get closer to your goal.
Meat-free Mondays: this is a great way to make sure you prioritise plant-based foods in your diet at least once a week.