Why Dietary Richness Is Linked to Longevity

Learn the science behind why dietary biodiversity can unlock powerful metabolic benefits linked to health and longevity.

When it comes to eating for health and longevity, most of us know the basics: eat more plants, cut back on processed foods, and focus on whole, nutrient-rich meals. But a fascinating new study from a large European cohort reveals that the diversity of species on your plate matters just as much as what you eat.

Dietary Species Richness (DSR) is a measure of how many different biological species you consume in your diet over a year. Unlike simply counting food groups or calories, DSR counts the unique species, like the variety of fruits, vegetables, grains, nuts, meats, and fish that make up your meals. Think of it as how many different “kinds” of plants and animals you eat, rather than just how much.

This study, published in the July issue of The American Journal of Clinical Nutrition, analyzed blood metabolite profiles of nearly 8,000 middle-aged, cancer-free Europeans across nine countries. The researchers wanted to uncover the biochemical signatures linked to eating more biodiverse diets and what those might mean for long-term health.

Why Biodiverse Diets Boost Longevity

By examining 32 plant polyphenols, 128 metabolites, and 39 fatty acid isomers circulating in people’s blood, the researchers discovered that higher dietary species richness was associated with a metabolic profile known to support health and longevity. Here’s what stood out:

1. Amino Acids 

Higher levels of essential amino acids like tryptophan and asparagine were linked to greater dietary species richness.

• Tryptophan, a precursor to serotonin, supports mood, immune regulation, and reduces inflammation.
  Sources: Turkey, chicken, eggs, cheese, nuts (especially almonds and walnuts), seeds (pumpkin, sesame), soy products (tofu, tempeh), and fatty fish like salmon.
  
• Asparagine supports healthy metabolism.
  Sources: Asparagus (named after this amino acid!), soybeans, legumes (lentils, chickpeas), whole grains, and dairy.
  

Lower levels of tyrosine and glutamate were observed, which is beneficial since elevated levels may signal metabolic stress and inflammation.

• Tyrosine: meats, dairy, nuts, seeds.
  
• Glutamate: protein-rich foods and dairy
  

2. Polyphenols

Polyphenols protect cells and support healthy aging. These compounds also promote gut microbiome health, enhancing systemic wellness.

• Epicatechin and Catechin: antioxidants with anti-inflammatory properties.
  Sources: Green and black tea, dark chocolate (70%+ cacao), apples, grapes, blueberries, blackberries.
  
• Enterolactone: a lignan metabolized by gut bacteria, linked to anti-oxidative and anti-inflammatory effects.
  Sources: Flaxseeds (richest source), sesame seeds, whole grains, berries, cruciferous vegetables (broccoli, Brussels sprouts).
  
• Kaempferol: a flavonoid with antioxidant benefits.
  Sources: Kale, spinach, broccoli, green beans, tea, apples.
  

3. Healthy Fats and Fatty Acids

Diverse diets supported higher levels of beneficial omega fatty acids critical for heart, brain, and metabolic health.

• Omega-3 Fatty Acids (EPA, DHA): reduce inflammation and support cardiovascular and cognitive function.
  Sources: Fatty fish (salmon, mackerel, sardines, anchovies, herring), flaxseeds, chia seeds, walnuts, algae-based supplements.
  
• Omega-6 Fatty Acids: essential for metabolism and immune function.
  Sources: Nuts (walnuts, almonds), seeds (sunflower, pumpkin), vegetable oils (safflower, sunflower, soybean), whole grains.
  
• Avoid Trans-Fatty Acids (TFAs): often linked to ultra-processed foods and increased cardiovascular risk.
  Sources: Partially hydrogenated oils in packaged snacks, fried fast foods, some margarines.
  Note: Naturally occurring TFAs in dairy and meat are less harmful.
  

4. Phospholipids and Sphingomyelins

These lipids maintain cell membrane integrity and support brain and metabolic health. Higher levels are linked to lower risks of chronic diseases including cancer.

• Phosphatidylcholines and Sphingomyelins:
  Sources: Eggs (especially yolks), organ meats (liver), fish and shellfish, soy lecithin, nuts, and seeds.
  

Interestingly, plant-based components of dietary diversity were the main driver of these beneficial metabolic changes, highlighting once again the importance of plant variety in your diet.

How to Put These Findings into Practice

• Aim to eat not just “more plants,” but more kinds of plants. Include fruits, vegetables, nuts, seeds, whole grains, and legumes from diverse species.
  
• Diversify your animal protein sources if you eat them: varying fish, poultry, and meats can contribute beneficial nutrients.
  
• Consider the quality, not just quantity, of foods: ultra-processed foods might contain many species but lack the beneficial nutrients and often include harmful additives.
  
• Enjoy seasonal, local, and traditional foods: these often add natural biodiversity to your diet.
  

Thinking about what you eat in terms of dietary species richness is an interesting take on past nutrition advice like: eat the rainbow.