Fruit Evolution: Why Tropical Fruits Are Healthier Than Temperate Fruits

Tropical fruits are the most underrated and neglected superfoods! The evidence on why tropical fruits are essential for optimal health is not only found in nutritional studies – it is based on human evolution. Let’s explore our unique relationship with exotic fruits and why they are even healthier than temperate fruits.

The evidence of the health-boosting properties of tropical fruits is finally mounting with the growing interest in those fruits in nutrition and health research. And, while the overall agreement on the importance of fruits in general for maintaining good health is firmly established in scientific research, most studies are done on fruits from colder climates. Tropical fruits are less investigated and rarely are considered a distinct food category… but there is a reason they should gain more importance as one of the most important foods for human health.

In this article, I will point out why tropical fruits play a distinct role for humans and the reasons they cannot be replaced with temperate fruits!

Tropical fruits are the ultimate superfoods for humans!

People living in the tropics have long known their importance for human nutrition, and a growing community of people adopting a fruit-based diet has discovered this secret to regeneration: Tropical fruits are superfoods for humans! And finally, tropical fruits are gaining more attention for their profound health benefits in scientific research. For example, a recent review concludes:

“Tropical and subtropical fruits may be considered as a very important source of nutrients and bioactive compounds, mainly flavonoids and non-flavonoid phenolics.”

Sayago-Ayerdi et al., 2021

A study on Brazilian fruits summarizes that “virtually unknown edible tropical fruits present significantly higher antioxidant activity when compared to temperate fruits considered to be good sources of antioxidants.” (Pereira-Netto, 2018). Even the seeds, peels, and other plant parts of exotic fruits have functional properties for health (see here) and are used in ethnobotanical medicine.

But not only wild and unknown tropical fruits are health-promoting. Edible, tropical fruits generally are a small nutrition miracle, like the well-known “ordinary” banana, which has a myriad of benefits like high content of minerals, vitamins, and phenolic, bioactive compounds. Read more on the nutritional benefits, omega-3 profile, and protein content of tropical fruits in our in-depth articles.

But why is it the tropical fruits in particular? Aren’t all fruits similarly healthy? Here’s where evolution gives us a new perspective on the importance of tropical fruits for human health:

What makes tropical fruits so special to humans?

Evolution gives us a simple yet pivotal explanation of why tropical fruits are essential for our health. And it’s nothing short of fascinating:

1. Humans are a tropical, frugivorous species!

Like our closest relatives, the chimpanzees, and our earlier ancestors, we are frugivores (fruit-eater). Further, humans originated in tropical forests and, thus, still are a tropical species. Tropical fruits are the primary food type in the human species-species-appropriate diet, which means that we have evolved with the nutrition of tropical fruits. Therefore, they are critical evolutionary foods and the primary component of our species’ biologically appropriate diet.

Humans have a frugivorous past and, thus, biological adaptations that specialize us in fruit-eating. Tropical fruits do not overstress the digestive, detoxification, and elimination systems, as the human body has evolved to do so. Here are just a few examples of adaptations in humans that make fruit-eating really easy, tasty, and healthy for us:

• Digestive anatomy typical for frugivores
• Complex hand with opposable thumbs, perfect for fruit picking and holding
• Dentition typical for frugivorous primates
• Sensory and instinctual cues: ripe fruits (attractive look, smell, and taste)
• Loss of vitamin C genes is a unique trait shared by highly frugivorous mammals
• Trichromatic specialized color vision (optimal to detect fruits) in frugivorous primates

Find the detailed article on more frugivore characteristics in humans here.

And if this list has not yet convinced you that our biological characteristics are perfect for eating fruits, watch a dog trying to pick a berry from a bush with his snout – because he can’t use his paws… it is one of the cutest things to watch, but… he just couldn’t do it. I helped him with my primate hand, adapted to pluck and hold fruits. Also, try offering a mango to your carnivorous cat…

But let’s dive into the difference between tropical and temperate fruits in terms of health:

2. Humans have co-evolved with tropical fruits, but not with temperate fruits!

Our evolutionary history with foods matters to understand our species-appropriate diet. The outcome of the mutualistic evolution between humans and fruits is a nearly optimal nutritional match, with high nutritional value and low toxicity (i.e., adapting to the plant’s protective toxic compounds in seeds or unripe fruits or inedible foods). As tropical frugivores, no wonder most wild tropical fruits are edible for us!

The dispersal syndrome: fruits evolve because of the frugivore

Have we coevolved with tropical fruits? Fruits of most tropical plants are relatively big, colorful, and aromatic in smell and taste, which pleases primates (inclusive humans).

Primates are relatively large seed-dispersing mammals, which can hold and transport bigger seeds with their complex hands and are sweet-lovers – unlike birds, which swallow seeds and mainly go for small sour fruits (see below). It’s widely accepted that fruits and the frugivore co-evolve:

The dispersal syndrome describes that the evolution of fruits trait (size, color, and scent) is driven by the choice of the animal that eats them. This is why ripe, tropical fruits taste so good (read more here)! On the other side, the seed disperser evolves anatomical and physiological traits to like, handle and digest the food, in this case, the fruit (see frugivore adaptations above).

Does the nutritional value of fruits also evolve with the frugivore?

What about nutritional traits? Do those coevolved fruits also have optimized nutrition for primates? This aspect of the “species-appropriate” diet is more difficult to prove, but food choices and foraging, as well as food source quality and nutrition, are certainly adaptive traits that significantly impact a species’ survival and reproduction.

Examples that show that nutrition in tropical fruits is optimized for humans are the optimal ratio of omega-3 compared to temperate fruits and the higher protein, fat, and sugar content found in wild tropical fruits needed to sustain relatively large mammals (like apes and humans). But also, the micronutrient profile is richer in tropical fruits than in other types of fruits.

Only tropical habitats offer enough food to sustain larger frugivorous mammals (and primates in particular) provided by the nutrition of (mainly) relatively large and sweet fruits during the whole year. Read more on that here.

Here is where we can rely on instinctual knowledge of animals: they eat only what they find appealing as food for a reason. Heck, animals were even found to self-medicate in the wild! Animals won’t eat what is not suitable and safe for them in the wild. Their diet in the wild has to deliver the nutrition they need to ensure the species’ survival and reproduction (evolutionary way).

The same is true for humans! The difference is that we alter the smell and taste of non-food items through cooking, seasoning, and sweetening, in such a way, that we have learned to like it. Interestingly, after extended periods of raw eating, most report disliking cooked foods they once liked.

Temperate fruits are originally bird food?

The “most matching” fruits for humans are those that are dispersed by primates, not birds. Most temperate fruits we eat today were original “bird fruits” that have been cultivated in order to be edible for humans. Exceptions are sweet berries, which are eaten by many mammals.

To find out if a fruit has evolved as a food source with a specific animal, we need to find out if the animal is a seed-disperser of the fruit (of the original “ancient” fruit before humans cultivated them). In the tropics, primates are important seed dispersers of fruits, but also birds, bats, and smaller mammals.

In temperate zones, it is mainly birds and mammals native to temperate regions (like rodents, foxes, badgers, etc.). Thus, some fruits are better suited for bird fruits than for mammals. On a side note: seed-dispersing is complex, and some fruits are eaten by birds and mammals. For the sake of better understanding, the concepts are being simplified and reflect tendencies, not absolutes!

Birds eat acidic fruits; mammals eat sweet fruits!

Generally, birds are the dispersers of more acidic fruits. Birds ingest the (tiny) seeds, and in some cases, avian digestion helps germination! In the wild, most “bird fruits” do not taste good to us, and often they are toxic. Birds disperse mainly seeds from the canopy, which also includes vines. Bananas, for example, are a sweet tropical fruit that is a typical food of primates and should only be fed to birds in moderation! It is not typical bird food.

In the tropics, there are uncountable fruits suitable for birds. Birds eat different types of fruits, but acidic fruits with small ingestible seeds are a perfect fit.

The sweeter, sometimes starchy, fleshy, and often bigger and big-seeded fruits are favored by primates. Those types of fruits are a perfect fit with their complex hands and preference for sweet taste. They also provide more energy and nutrition, which is essential for larger mammalian animals like apes (but also larger birds that like to eat sweet fruits, like toucans).

Unlike primates, birds cannot taste sweetness – except for hummingbirds which are sweet nectar-eaters (nectarivore).

Generally, birds do taste sour (acidic). Humans and omnivores that naturally eat sweet foods with simple sugars (fruits), are able to taste sweet. But not carnivores and granivores (grain eaters, like birds)!

Are temperate fruits “bird food” which we have cultivated to suit human consumption?

In temperate climates, there are simply no large wild sweet fruits for primates, and thus, no frugivorous primates exist there! This is one more hint that temperate climates are not the optimal environmental condition for humans. Let’s look at the evolutionary background of fruits and seed-disperser in temperate climates:

Most fruits that grow in temperate climates have a high acid content and lower sugar content than sweet fruits (tropical fruits). Before humans cultivated temperate fruits extensively, they were smaller and more acidic – which raises the question:

Have the temperate fruits we eat today evolved as foods for birds?

Temperate fruits have co-evolved with fruit-eater animals native to the temperate zones. Most wild temperate (and sub-tropical) fruits are avian (bird) fruits, not human fruits. In temperate zones, there are no bigger frugivorous mammals because the climate does not support the growth of trees, which could sustain larger frugivores. Thus, temperate fruits originally were not edible (and some even toxic) to humans until we cultivated and bred them to be larger and sweeter – and in essence, resemble more tropical fruits.

Temperate fruits were small and sour before cultivation

Most of our cultivated fruits in temperate zones are hybrids and were significantly altered in their nutritional and biological properties to be suitable as human foods and please our taste buds. Most of the fruits in the US and Europe result from crossing and extensive breeding. The wild peach, for example, is around 2.5 cm small and tastes “earthy, sweet, sour and salty”, more like “a lentil” (see here). While tropical fruits also went through cultivation and breeding for optimization, it is a fact that wild fruits are perfectly edible for humans and are the main foods of other apes, i.e., chimpanzees. It seems that tropical fruits are also quite difficult to breed for “improved” fruit traits.

The ancient apples, for example, are small and sour, similar to crabapples before we bred them to have bigger and sweeter fruits – to resemble our tropical fruits. Crabapples resemble more the wild rose hip than our modern apples – and are perfect bird food during winter. This article has a detailed description of how perfect crabapples are for birds. The crabapple is just one example to explain why temperate fruits are originally bird food. 

Our modern temperate fruits are still acidic

Despite domesticating fruits for hundreds or thousands of years, there are limitations to breeding temperate and subtropic fruits in terms of acidity and sweetness. Temperate fruits are still smaller and more acidic than bigger, sweet tropical fruits. For example, blueberries, nectarines, pomegranates, apples, cherries, and oranges all have a pH between around 2.9 and 4.5 (values from here). Sweet tropical fruits, like papaya, mango, cantaloupe, and bananas, range somewhere from 5 to 6.6 pH.

Eating acid or underripe fruits is also the main reason that raw vegans see dental erosion – a problem birds luckily cannot experience.

Are temperate fruits healthy, too?

Most temperate and acidic fruits have evolved as food for seed-dispersing “birds.” Can a frugivorous mammal thrive on fruits for birds? Can we still enjoy the cultivated temperate fruits we love? Yes, because we have sped up evolution through cultivation, but our evolutionary and, thus, optimal foods that can sustain us are tropical foods that we have evolved to eat. But temperate fruits are not optimal for us because we haven’t co-evolved with those fruits and their nutritional and phytochemical makeup, like flavonoids, alkaloids, acids, and other potent chemicals. That said, eating temperate fruits as an addition is perfectly fine, as locally grown fruits that ripen on the tree are superior in quality.

Learn more about the biologically appropriate diet of humans and supplements to consider when living in a temperate or cold country here.

Read more about different fruit types and categories here.

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