Fruits: A Wonderful and Diverse Component of a Balanced Diet
Fruits are a wonderful and diverse component of a balanced diet. Eating whole, fresh and locally produced in-season fruits is one of the best and most delicious ways to acquire a wide spectrum of macronutrients, micronutrients and phytonutrients, help prevent and manage diabetes, and support sustainable agricultural practices that ensure the health of the planet.
Fruit Botany
Botanically speaking, any “organ” that contains seeds is considered a fruit, and fruits are only produced in flowering plants. Flowers are pollinated, fertilized ovules are what become the seeds, and the surrounding tissue becomes the flesh of the fruit, and in fact is the ovary wall. This scientific definition and description of fruit means that many healthful whole foods that humans refer to as vegetables, nuts and seeds, beans and legumes, spices and whole grains in culinary practice, actually are botanical fruits.
As fruits ripen, they build up large amounts of natural sugars in their flesh, and the seeds also become more durable as they mature (which allows them to be transported). This resulting “sweetness” in ripe fruits is the clear preference of humans, as it is for most other animals that eat plants. Many animals, including our endangered ape cousin the orangutan, as well as a great variety of bird species, some bats and the maned wolf, are classified as “frugivores.” This means the majority of their diet consists of eating fruit, with a preference towards ripeness and sweetness. The evolutionary explanation for preferring sweetness is that this taste is an indication of a food high in energy (the sugars enter into the bloodstream as glucose which is absorbed into the cells of the body with the help of insulin), which gives an advantage for survival.
Fruit and The Biodiversity Link
The eating of ripe fruits is critical to biodiversity and balanced ecosystems as well. As fruits are eaten by different animals, their seeds are dispersed over wide ranges and given the chance to grow anew and provide sustenance to more animal life. This symbiotic “mutualism” can be delicate, and lost species(both plant and animal) due to a range of issues and practices, such as deforestation, pollution and climate change, can have reverberating negative effects on entire ecosystems.
Based on the nutritional values and clear evolutionary propensity of humans and many other animals to forage and disperse the seeds of ripe fruits, it is not hard to find a lot of claims that humans are naturally frugivores, or herbivores. There is little hard evidence to back-up these claims however, and most research has confirmed that humans have been eating a tremendous variety of diversified diets around the planet for tens-of-thousands, if not hundreds-of-thousands, of years. Fruits, therefore, are an essential component of a balanced and diversified diet.
Types of Fruit
There are several different ways to categorize the abundant range of botanical and culinary fruits. One way is to define simple fruits (coming from a flower of only one pistil), aggregate fruits (multiple carpels within a flower) and multiple fruits (multiple flowers). Another way is to separate fleshy fruits ( typically identified as “fruits” by the common consumer) and dry fruits (like nuts, seeds, beans and wheat kernels, for example). Fleshy fruits can then be broken up into some of the more common fruit categories likely to be encountered at a local farmers market, produce stand or supermarket.
- Simple fleshy fruits include:
- Berries, blueberries, grapes, avocados, guavas, etc…
- Stone fruits, also called drupes, include:
- Peaches, Plums, Cherries, etc…
- Citrus fruits, referred to more correctly as Hesperidium, include:
- Oranges, lemons, limes, grapefruit, etc…
- Pome fruits
- Apples and Pears
- Some common aggregate fleshy fruits include:
- Blackberries and raspberries, and multiple fleshy fruits like figs and pineapples.
- Certain “vegetables,” such as:
Exotic Fruits
There are thousands of other edible fruit varieties that are less globalized and commercially produced and distributed. The majority of these “exotic” fruits come from warm tropical and subtropical regions of the world. They are a great joy to explore, with diverse flavor profiles and sociocultural associations. Acai, mangosteen, passion fruit, uchuva and dragon fruit are but a few examples. Sometimes these lesser-known fruits are packed so full of valuable nutrients in comparison to most commercially cultivated fruits, that they earn themselves the marketable label of “superfood.”
Whole Fruits
Whole fruits are very high in micronutrients and phytonutrients, like vitamin C, magnesium, and flavonoids, as well as macronutrients such as carbohydrates(sugars) and dietary fiber. The fiber helps to slowly digest and absorb the micronutrients and macronutrients in the whole fruit, providing the body with healthy and gradual energy(glucose) that does not result in major spikes in blood glucose levels. Fruit juices, even 100% fruit juices, can still contain a lot of micronutrients, but lack in dietary fiber and are much higher in carbohydrates. This results in fruit juices having a higher glycemic load than the whole fruits they are derived from, and their consumption potentially increases the risk of developing type 2 diabetes, as opposed to preventing it.
Diets based around whole plant foods, including fresh fruits, have consistently demonstrated an overwhelmingly positive impact in the prevention of numerous chronic diseases, including type 2 diabetes. Focusing specifically on fruits and diabetes, berries have been shown to be particularly effective in helping to regulate blood glucose levels and prevent insulin resistance and type 2 diabetes. Blueberries, grapes and the pome fruit apple, also showed strong anti-diabetic properties in another study.
Note: Classifications of fruits, vegetables, seeds and grains will follow mostly “culinary” definitions, though it is good to keep in mind that botanically many culinary vegetables, such as cucumbers, carrots, tomatoes and squash, as well as legumes like peanuts and beans, nuts such as walnuts and hazelnuts, and even certain grains like wheat, are technically fruits. Furthermore, sub-categories of fruits such as berries sometimes botanically contain some surprises, such as avocados, and do not contain certain “aggregate”(develops from multiple ovaries, as opposed to “simple” fruits which develop from one ovary) fruits such as culinarily defined berries, including raspberries and blackberries.
Discover More Healthful Whole Fruits and Their Role in Diabetes Prevention and Management
Resources and Further Reading
An accessible guide to the different kinds of botanical fruits: http://www.biologyreference.com/Fo-Gr/Fruits.html
History of the “sweet tooth”: https://www.smithsonianmag.com/arts-culture/the-evolution-of-the-sweet-tooth-79895734/
A publication about frugivores and seed dispersal and ecological importance: https://pure.au.dk/ws/files/121439005/onstein_NatureEcolEvol_2017.pdf
Evidence through advanced scientific analysis of faecal matter showing the diverse diets of early humans and other primates: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4465628/
Plant-based diets, including fruit, and the ability to help prevent diabetes: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002039
The preventative potential of consuming whole blueberries, apples and grapes for type 2 diabetes: http://www.bmj.com/content/347/bmj.f5001
Berries shown to be particularly effective in preventing type 2 diabetes: https://academic.oup.com/ajcn/article/99/2/328/4571480
The Ark of Taste is a searchable database of endemic foods, with many fruits, from around the world, and developed by Slow Food: https://www.fondazioneslowfood.com/en/what-we-do/the-ark-of-taste/
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