Several types of sugar are eaten. All come from plants. Sugar is stored in most plant tissues for their energy needs.
Sugar is a loose term scientifically, as it refers to a few categories of carbohydrates: monosaccharides, disaccharides, and oligosaccharides. Almost all sugars are of the formula CnH2nOn, where n is between 3 and 7.
Monosaccharides are the simplest sugar. They include, among others: glucose, fructose, and galactose. These 3 sugars are directly absorbed into the bloodstream during digestion. Though they differ in structure, all share the formula C6H12O6.
Monosaccharides form the building blocks of disaccharides (such as sucrose) and polysaccharides (such as cellulose and starch).
Glucose and fructose together form sucrose (C12H22O11). White (or brown) granulated table sugar is sucrose.
Glucose is the simplest sugar; one of the primary products of photosynthesis. Glucose is the favored fuel for cellular respiration because of its nonspecific reaction with protein amino groups, and its conformational stability.
Fructose is fruit sugar; an isomer of glucose. Fructose is found in flowers, fruits, berries, and most root vegetables.
Commercially, fructose is derived from sugarcane, sugar beets, and corn. Its crystalline form is pure fructose, while high-fructose corn syrup is a mixture of glucose and fructose as monosaccharides. Honey is a glucose-fructose mix.
The 5-ring form of fructose is 1.73 times sweeter than sucrose. The 6-ring form is equivalently sweet. Warming fructose creates the 6-ring form.
Hydrogen bonding – between positively charged hydrogen atoms and electron-rich atoms such as oxygen – determines the sweetness of a sugar. Sweeter sugars have tighter, stronger hydrogen bonds.
Fructose has been favored commercially because its sweetness is perceived quicker than either sucrose or glucose, its taste sensation peaks higher than sucrose while diminishing more quickly, and it has a sweetness synergy effect when combined with other sweeteners.
Galactose is less sweet than glucose. Lactose (C12H22O11), found in milk, is the disaccharide combination of glucose and galactose.
Disaccharides are broken down into monosaccharides during digestion; either hydrolyzed via hydrochloric stomach acid or by enzymes in the intestines.
Oligosaccharides are a carbohydrate (saccharide) polymer, typically comprising 2–10 simple sugars. Oligosaccharides serve several functions, including, by their presence in animal cell membranes, cell-to-cell recognition. Plants bundle up oligosaccharides for transport and storage.
Sugarcane was domesticated on the island of New Guinea 10,000 years ago, before grains were sown anywhere in the world. Natives cut the cane, chewing a stalk until a starburst of sugar hit.
Sugar featured predominantly in New Guinean myths: an elixir for curing all kinds of ailments, and an answer for malcontent moods. Priests at religious ceremonies sipped sugar water from coconut shells.
Sugar spread slowly among the Southeast Asian islands, reaching the mainland by 1000 bce. By the mid-4th century ce, Indians had learned how to process sugar into a powder. It was used as a curative for headaches, stomach flutters, and even impotence.
Sugar refinement was long kept a secret science, passed from master to apprentice. By the 6th century the craft had crept to Persia, where rulers entertained guests with sugary sweets.
Arab conquests carried sugar with them. The sweet knowledge spread throughout the Muslim world: in the Arabian Peninsula and as far as Spain.
The Arabs perfected sugar refinement and transformed it into an industry. The work was brutal: the heat in the fields, the smoke in the boiling rooms, the crush of the mills.
Sugar demand surged. The work was considered suitable only for the lowest laborers. Field hands were commonly prisoners of war: east European captives of the Ottoman Empire – one of the fruits of conquest.
The first Europeans to succumb to sugar were British and French crusaders who sallied forth to enrich themselves by wresting the Holy Land from the infidels. Those that returned brought with them a sweet powder so rare that it was classified as a spice, consumed only by nobility.
The Western elite who had fallen under sugar’s spell faced a dilemma: deal with the southern European suppliers at exorbitant prices, defeat the Turks, or suss new sources of sugar. The last option seemed the most economical solution.
The European age of exploration was, to no small extent, a search for territories that would support growing sugarcane. Cane is not productively produced in temperate climes. It requires rain-drenched tropical fields to flourish.
In 1425 the Portuguese prince Henry the Navigator sent sugarcane and colonists to Madeira, an island just rediscovered in 1420. The crop soon made its way to other newly found Atlantic islands.
In 1493, cane was carried on Genoese explorer Christopher Columbus’ 2nd voyage to the New World. Whence dawned the age of Caribbean sugar. Columbus’ sugarcane was first planted in Hispaniola, the site a few hundred years later of a great slave revolt.
The price of sugarcane was devastation. The rainforests of Jamaica, Cuba, and elsewhere were razed. The natives were killed, subjugated, and enslaved. The Portuguese turned Brazil into a boom colony, with over 100,000 slaves producing tons of sugar.
During the mid-17th century, by dint of surfeit thanks to slavery, sugar was transformed from a luxury spice to a staple, first for the middle class, and eventually the poor. Economists call this feedback loop a virtuous cycle: surging supply creating increasing demand via falling prices.
By the 18th century, sugar and slavery had proved a winning formula. Every few years a Caribbean island was colonized, cleared, and planted.
When the natives expired, they were replaced by African slaves. Over 11 million slaves were shipped to the New World. More than half worked on sugarcane plantations. Millions were tortured, mutilated, and died to satiate Europe’s growing sweet tooth.
In 1700 the average Brit ate 1.8 kilograms of sugar a year. By 1800: 8 kilos. In 1870, the average appetite was up to 21 kg per person per annum. By 1900, individual sugar consumption was 45 kg a year.
Breakfast cereal began its commercial descent in the 1880s, when it was first packaged as a whole-grain health food. In the 1920s, cereal began its evolution into sugar-coated puffs, flakes, and pops. From there cereal’s popularity bloomed. The US trademark office now lists 2,000 different commercial cereal names.
Recent decades have seen a burgeoning consumption of processed sugars. Over the past 50 years, sugar consumption has tripled worldwide. Now, more than 500 calories per day come from refined sugar alone for people in many parts of the world. That is often more than a quarter of dietary energy intake.
High-fructose corn syrup (HFCS) is manufactured from corn syrup in a process that yields a mixture of glucose and fructose in roughly equal proportions. Corporations that grow corn are subsidized by the government in the United States, so HFCS is pervasive.
The average American sucks down 23 kilos of corn syrup per year. Most other developed countries eschew HFCS, relying instead on sucrose as an added sugar.
It seems like every time I study an illness and trace a path to the first cause, I find my way back to sugar. ~ American nephrologist Richard Johnson
Bodily, sugar acts addictively in multiple ways. Sugar unbalances the hunger hormone ghrelin. Sugar disrupts leptin, a hormone helpful to feeling sated. Sugar dupes dopamine signaling to reduce the pleasure from food, compelling greater consumption.
Overconsumption of derived fructose over time can lead to liver toxicity and a host of other chronic diseases. While glucose is readily metabolized by all cells, the liver hogs fructose for processing.
Fructose engenders uric acid production, which raises blood pressure. That fructose damages the liver like alcohol comes as no surprise in considering that alcohol is derived from fermented sugar.
The average American consumes the equivalent of 22.7 teaspoons of sugar each day. The upshot has been a rocketing of diabetes in the population, from 2% in 1973 to over 7% by 2013 and still climbing.
In 1900, only 5% of people worldwide had high blood pressure. The pressure has built. Now 1/3rd of adults on the planet are closer to expiration from cardiovascular disease.
Through animal experiments, including humans, English physiologist John Yudkin showed in the late 1950s that a high sugar diet led to elevated levels of insulin and fat in the blood; risk factors for diabetes and heart disease. His well-researched message was drowned out by reductionist biochemists jumping to wrong conclusions about the source of dietary health problems.
Along the same lines as sugar being satisfactory food, eggs got blamed for their cholesterol, and fats for being fatty. Instead, eggs are healthsome, albeit too high in protein, and healthy plant-based fats in the diet should be most welcome in moderate measure.
Much of the misdirection in not attributing sugar as the culprit of dietary distress came from the sugar industry, which paid scientists to find fault with fat instead. (A 1965 study that found ill effects in rats on a high-sugar diet had its funding by the sugar industry terminated just before completion. The damning evidence was never published.) Playing nutritionists like pawns, a half-century of dietary recommendations were shaped by the sugar industry. Unsurprisingly, the American Medical Association was duped (doctors receive no education in research methodology and lack the skepticism that comes on the coattails of being a lawyer).
They were able to derail the discussion about sugar for decades. It was a very smart thing the sugar industry did because review papers, especially if you get them published in a very prominent journal, tend to shape the overall scientific discussion. ~ American educator Stanton Glantz