Most of us have heard the advice to get our “five-a-day” when it comes to fruits and vegetables. But new research from King’s College London suggests that it’s not just how many plants you eat, it’s how many different kinds.
In a study published in Clinical Nutrition, researchers analyzed data from more than 670 UK adults and found that those who ate a wider variety of plant-based foods — including vegetables, fruits, nuts, seeds, herbs, spices and even plant-based oils — had better cholesterol levels, improved blood sugar markers and higher intakes of key nutrients than those with less diverse plant diets.
“Current dietary guidance in the UK often emphasises quantity, such as ‘5-a-day’ for fruit and vegetables,” said Dr. Eirini Dimidi, senior author of the study. “Our findings suggest that dietary variety, across all plant-based food groups, may be just as important for improving diet quality and lowering the risk of cardiometabolic diseases.”
The research grouped participants by how many different plants they ate each day: about 5.5 on the low end, around 8 in the middle and roughly 11 for those with the most diverse diets. For every one-unit increase in plant diversity, blood sugar markers improved and those with higher diversity also had higher levels of HDL, or “good” cholesterol.
Still, the study found that nutrient-dense foods like nuts, seeds and legumes barely contributed to most people’s diets, and even the most plant-diverse eaters fell short on fiber and some key vitamins and minerals.
Dr. Dimidi suggests making small, easy changes: “In addition to fruits and vegetables, legumes, nuts, seeds, herbs and spices are great plant-based food sources that can help us to introduce more plant diversity into our diets. Try adding nuts to your porridge or spices to your baked beans. Branch out from the usual peas, onions or carrots with dinner, and try incorporating seasonal vegetables like courgettes, broccoli and broad beans.”
The team has also received £1.5 million from the Biotechnology and Biological Sciences Research Council for a follow-up trial to see how boosting plant diversity affects gut and heart health over time.
This particular study did not receive any specific grant from public, commercial or not-for-profit funding agencies.