The Ecology of Humans – Fruit

Fruit

Fruit was a plant invention to tempt animals into seed dispersal and provide nourishment to herbivores without literally getting eaten alive – in other words, a diversionary stratagem.

The common take is that fruit is a meaty sugar with seeds. To a botanist, fruit comprises the ripened ovaries of plants, including the seed within. That definition – an ovary with seed(s) – is insufficient, as the definition also encompasses various nuts, grains, and vegetables.

A workable definition of fruit is a sweet-tasting gift by a flowering plant in a gambit to disseminate its seeds. By that characterization, there are ~2,000 distinct fruits in the world.

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From an evolutionary perspective our sweet tooth descended from eating fruit. Most of the carbohydrates in hominids’ diets were found in fruits.

Fruit is readily accessible energy, typically with other wholesome ingredients tucked in. The fructose content of fruit is surprisingly small compared to its satisfying sweetness.

Starchy carbohydrates require greater digestion for equivalent energy. Whereas fruit sugar is an immediate energy rush, complex carbohydrates give up their sugars at a more measured pace.

22 MYA, the African canopy was a year-round rainforest. Apes survived on the fruit from trees.

5 million years later, global cooling curtailed the fruit output, bringing a seasonality that spelled starvation. Hominids genetically adapted by becoming highly efficient fructose processors. Even small amounts in excess were stored as fat; a huge survival advantage for sweets that cannot be had year-round. Humans descended with the proclivity to tuck surfeit sugar away.

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A brief survey of select fruits follows. (The fruits described were chosen based upon something interesting to convey. Practically all edible fruits are nutritious.)

Açaí

The açaí palm is native to the swamps and floodplains of tropical Central and South America. It produces a small, round, purple-black drupe. A drupe is an indehiscent (not opening at maturity) fruit in which a fleshy outer part surrounds a shell – pit or stone – with a seed inside. Apricot, cherry, mangoes, olives, peach, plum, and most palms, such as coconut, produce drupe fruit.

The açaí berry burst into popularity in 2004 as a dietary supplement, with marketers making unfounded claims of its exuberant health properties, particularly its antioxidant potency. Internet hype was particularly intense in 2008–2009. For all that, there is no scientific evidence that açaí offers any especial health benefits beyond any other berry.

Apple

The deciduous apple tree originated in the mountains of central Asia. The apple was one of the first cultivated fruits and is one of the most widely grown tree fruits. There are over 7,500 apple cultivars, variously bred for tastes and uses: eating fresh, cooking, or for cider.

The apple has symbolically figured in many cultural mythologies. In Norse mythology, the goddess Iðunn gave apples to the gods that grant them eternal life. To the Greeks, the apple was a symbol of love.

For Jews and Christians, the apple symbolizes temptation to evil. In the Biblical book of Genesis, Eve picked this forbidden fruit in Eden and coaxed Adam to share it with her. Hence, the allegorical downfall of man was brought about by temptation offered by women; very heavy symbolic sexism, as well as an apt observation on the weak wills of men.

‘Conventionally’ grown apples in the United States are loaded with pesticides. One is diphenylamine (DPA), a carcinogen banned in Europe. DPA is sprayed on 80% of conventional apples after harvesting to slow browning. The US Apple Association asserts “there is no cause for concern, and certainly not a safety issue.” The US EPA has not looked at DPA since 1997.

Apples offer dietary fiber, phytonutrients, and copious vitamin C. And, reputedly, an apple a day keeps the doctor away.

Apricot

The apricot is a small tree that produces small golden fruit. The Chinese cultivated apricots over 4,000 years ago. Silk Road trade took the apricot to Iran, where the Greeks and Romans discovered it during the 1st century ce.

Fresh apricots are succulently delicious, but they do not travel well: hence the popularity of dried apricots, typically preserved with sulfur dioxide, which turns the fruit a vivid orange.

In Europe, apricots earned a reputation as an aphrodisiac. Shakespeare’s A Midsummer Night’s Dream (1597) dreamily suggests such.

Apricots offer dietary fiber, antioxidants, vitamins A, C, and E, iron, copper, manganese, potassium, and zinc. Apricot nutrients benefit the cardiovascular system.

Apricot seeds, which have anti-herbivore cyanogenic glycosides, have long been employed medicinally. Apricot seeds were used against tumors by the 6th century. During the 17th century in England, apricot oil was also used against ulcers.

Avocado

An avocado is a large berry with a single seed. The avocado tree is native to Mexico and Central America. Avocados are now cultivated commercially in tropical and Mediterranean climates throughout the world.

Avocado trees are partially self-pollinating. Trees are often propagated via grafting to maintain predictable quality.

There are numerous avocado cultivars. Hass is the most common. All Hass avocados descended from a single tree raised by American mail carrier Rudolph Hass of La Habra Heights, California.

Avocados are nutrient-dense. About 75% of the energy supplied by avocados comes from its healthy fat. Avocado is an excellent source of dietary fiber, vitamins B, C, E and K, potassium, magnesium, and antioxidants.

Avocado is a good food for infants, and for those who are overweight, as gives a solid sensation of satiation.

Banana

Bananas are the edible fruit of numerous different trees in the Musa genus, indigenous to Southeast Asia and Oceania. The earliest evidence of banana cultivation comes from eastern New Guinea 6,500 years ago. Portuguese sailors brought bananas to the Americas in the 16th century.

After the American Civil War, multinational banana companies established plantations in what were later called the “banana republics” of Central America. By the 1920s, the banana was one of the most popular fruits in the US.

By far the most important commercial banana cultivar is the Cavendish (Musa acuminata), particularly the Dwarf Cavendish, owing to its ease of transport, shelf life, and taste. Grand Nain (Chiquita Banana) is another popular banana.

Export bananas are picked green. They ripen in air-tight rooms after arriving in their destination country. Ethylene gas is pumped into these rooms to induce ripening. The vivid yellow color of the supermarket banana comes from the artificial ripening process.

Bananas used in cooking are called plantains, which are starchier than Cavendish.

Bananas an excellent source of dietary fiber and vitamin B6. They also contain vitamin C, manganese, and potassium.

Blueberry

Blueberries are indigenous to North America, but interest in the blue food has spread globally. The blueberry was long an important food to native Americans. They were first cultivated in 1908, making blueberries the most recent wild fruit to become a commercial crop.

In North America, blueberry season begins in May and ends in late summer. Maine – the largest producer of blueberries in the US – plasters its blueberries with pesticides, creating a badly polluted treat.

Blueberries are rich in vitamins C and K, antioxidants, and manganese.

Cherry

The cherry originated near the Caspian Sea. By 300 BCE the Greeks were cultivating cherries. The Romans spread cherries throughout Europe and Asia minor. Cherries came to North America by way of early English and French settlers.

Today there are ~1,200 cultivars of cherries; 900 of the sweet variety, 300 sour. Cherries grow in temperate latitudes.

The cherry tree is especially beloved in Japan as a spiritual metaphor, where the short-lived April blossoms are a reminder of the transience of existence. The summer cherry fruiting season is also short.

Cherries offer dietary fiber, vitamin C, potassium, and phytonutrients.

Citrus

Citrus are acidic fruits; typically juicy, always nutritious. All share a commonality of tangy flavor and sweet-sour aroma.

Citrus are especially high in vitamin C. They also provide B vitamins, dietary fiber, potassium, calcium, phosphorus, magnesium, copper, and various phytonutrients.

The origin of citrus remains unresolved, but indications are tropical Southeast Asia or Australasia. The earliest reference to citrus is in 2200 bce Chinese texts.

Mandarin and sweet oranges originated in China. Lemons were first grown in India. After citrons and lemons made their way to the Mediterranean during Roman times, their rarity made them status symbols among the elite.

Because citrus trees easily hybridize via grafting, there are innumerable citrus fruits. Major varieties include citron, grapefruit, kumquat, lemon, lime, orange, tangelo, and tangerine.

Date

The righteous man will flourish like the palm tree. ~ Psalms 92:12, The Bible

The date palm probably arose in the Near East over 50 million years ago. Date palms has been cultivated at least since 7000 bce. There are dozens of mentions of date palms in the Bible and Koran. Dates have been a staple food in the Middle East and Indus Valley for thousands of years.

Trade spread date palms to tropical lands throughout the world. There are numerous cultivars.

A date palm takes 4–8 years to mature before producing dates. It may then provide copious fruit for a decade.

Palms may live for 150 years. Commercial cultures are replaced at an earlier age.

Date palms grow to 23 meters high. The date palm is dioecious (separate male and female plants). Both sexes bear fruit.

Dates ripen in 4 stages, denoted throughout the world in Arabic: kimri (unripe), khlal (full-size, crunchy), rutab (ripe, soft), and tamr (ripe, sun-dried).

A ripe date is 80% sugar. The rest is dietary fiber, protein, fat, and mineral matter.

Dates possess plenty of potassium. They also offer copper, manganese, magnesium, selenium, and zinc.

Dates are particularly beneficial to women in their last month of pregnancy, as they ease childbirth labor.

The sap of the date palm is used as a beverage, often fermented into an alcoholic liquor. Sap extraction injures the tree, so typically only unproductive date palms are tapped for sap.

Fig

The dioecious wild fig originated in western Asia. It spread to the Mediterranean in prehistoric times.

Figs were cultivated 6,000 years ago. The fig has been food for slaves and upper crust alike for millennia.

Although the fig is considered a single fruit, the seeming seeds within are actually over 1,000 tiny fruits. The fig itself is a fruit ensemble (infructescence). The complex flower cluster (inflorescence) comprises a hollow fleshy syconium that is lined with numerous unisexual flowers.

Figs do not suffer the tap of sap that dates palms do. Avoiding herbivory, fig stem sap is an irritant to human skin.

Grapes

It is good neither to eat flesh, nor to drink wine. ~ Romans 14:21, The Bible

A grape is the fruiting berry of deciduous woody vines in the Vitis genus. These vines are one of the earliest cultivated plants. Wine was made from grapes in the south Caucasus 6000 bce.

The grape’s popularity owes to its easy fermentation and a fondness for alcoholic beverages. Yeast that naturally live on the skin of grapes led to discovery of wine.

There are 10,000 grape cultivars from the 65 different grape species. The color of grapes ranges from white, yellow, green, orange, pink, crimson, dark blue, to black.

From the ancient Greeks onward, every European culture has embraced wine in its cultural traditions. Though the Bible is conflicted on the substance, wine has long held a prominent position in Christian ritual.

Wine cheereth God and man. ~ Judges 9:13, The Bible

In contrast, the Koran is clear-cut in disdaining intoxicants, notably alcoholic beverages.

Intoxicants are but defilement from the work of Satan. ~ Surat Al-Mā’idah (The Table Spread) سورة المائدة 5:90, The Koran

Today, wine consumes 65% of the grapes grown. The remaining 35% is eaten as table grapes and raisins, and drank as grape juice.

Grapes and raisins can be toxic to dogs. Yet some dogs eat grapes with impunity. The cause of the problem is not known.

For us, grapes provide vitamin C, K, antioxidants, and other phytonutrients, notably resveratrol. Plants produce resveratrol to fight off fungal and bacterial pathogens. Peanuts are a significant source of resveratrol.

A glass has been raised to red wine, in most modest moderation, as being beneficial to cardiovascular health. Resveratrol has been pin-pointed, along with antioxidant activity.

The anecdotal evidence for red wine’s positive power is called the French paradox. The French people have a relatively low incidence of coronary heart disease despite a diet rich in saturated fats. The red wine that washes French food down is credited as offsetting the otherwise deleterious effect of diet.

That wine is beneficial to health is as scientifically convincing as the hokum of homeopathy and the tooth fairy. At best it is a confusion of correlation with cause, which is the frequent and grievous methodological mistake of scientists.

Olive

The olive is a small evergreen tree found in much of Africa, the Mediterranean basin, the Arabian Peninsula, and southern Asia as far east as China. The olive has been cultivated for at least 6,000 years.

The fruit is a small drupe 1–2.5 cm. Olives are harvested in the green to purple stage.

80% of the calories in olives are oleic acid, a monounsaturated fatty acid. Olives have a high phytonutrient content, including antioxidants. Olives have unique anti-inflammatory properties.

Peach

The peach is native to northwest China, where it has been cultivated for 4,000 years. The tree – cousin to cherry and plum – spread westward through trade, reaching Greece by 300 bce.

Peaches’ fuzzless sister – nectarines – have been around for at least 2,000 years, but their first mention is from medieval French. Peaches have been known to grow on nectarine trees and vice versa.

Like date palms, peaches and nectarines are dioecious.

Peaches and nectarines have either white or yellow flesh. The fruit is classified as either freestone – where the seed easily separates from the fruit, or clingstone – where the seed adheres to the fruit.

There are hundreds of peach and nectarine cultivars.

Nectarines have twice as much vitamin A as peaches and are a richer source of potassium. Peaches are one of the few fruits to have a significant amount of niacin (B3). Peaches and nectarines also offer dietary fiber and various phytonutrients.

Plums

The plum was one of the first domesticated fruits. Neolithic plum remains have been found at archeological sites, along with olives, grapes, and figs. Plums originated in the Caucasian mountains and northern Asia.

Depending upon taste in taxonomy, there are 19–40 plum species, but only 2 are of worldwide commercial significance. There are well over 1,000 plum cultivars, of which a few dozen are popular.

Plum trees may naturally grow to 12 meters in height and 10 meters across. Commercial plum trees are usually half that size.

Plum fruit ranges from tart to sweet. The skin may be particularly tart.

Besides eaten fresh, plums are prepared in a variety of ways, including being dried, salted, or pickled. A prune is a dried plum. Whereas most plums grown for fresh consumption are clingstone (a difficult-to-remove pit), prunes are typically freestone cultivars (the pit is readily removed).

Plums have the typical phytonutrients and are high in vitamin C. Prunes are particularly prized for their laxative effect. Daily consumption of a few prunes promotes proper bowel function.

Raspberry

The raspberry is native to Asia, Europe, and North America. While the fruit is very perishable, the plants are hardy. Raspberry bushes grow well in cool climates and can withstand wintry weather.

The ancient Romans spread the raspberry throughout their empire beginning 2,000 years ago. While the red raspberry is best known, there are black, purple, and blue raspberries in North America.

Though delicate, raspberries represent a robust bounty of dietary fiber, vitamins C, E, and K, phytonutrients, manganese, and magnesium.

Strawberry

Different species of strawberry are indigenous to both the Old World and New. The familiar garden strawberry is a cross between a small tasty berry from eastern North America and a larger, less flavorful berry native to Chile. This mating took place in mid-18th century France.

Strawberries are unusual in that the apparent seeds, which are actually ovaries, are on the outside of the fruit, and the flesh is part of the flower.

Another oddity is the name. What the “straw” in strawberry supposedly means has been lost.

Strawberries are stuffed with vitamin C, B9, manganese, dietary fiber, and phytonutrients. Strawberries are good for the cardiovascular system and have anti-inflammatory and anticancer properties.