Intro
There are times, such as Super Bowl parties or holiday feasts, when people jokingly complain that they have "overdosed" on food. While those extra helpings of turkey or taco dip might, at worst, give you a bad case of indigestion, there are foods out there that can seriously harm you if you eat too much of them.
Here's are seven foods that prove that you really can have too much of a good thing.
Carrots
Carrots are full of vitamins, minerals and fibers that are good for your health. But eating too many carrots can bring in too much beta-carotene the molecule responsible for carrots' bright orange hue and a precursor of vitamin A. This can lead to excess blood carotene which can discolor the skin.
Known as carotenemia, the condition occurs because carotene is a fat-soluble molecule. Excessive quantities of it tend to accumulate in the outermost layer of skin, resulting in yellow- or orange-pigmented skin, particularly in the palms, soles, knees and nasal area.
Although carotenemia occurs mostly in infants when they are fed too much pureed carrot baby food, it can occur in adults as well. In a case report published in The Journal of Dermatology in 2006, a 66-year-old woman's skin turned yellow-orange after she took too many carotene oral supplements. One cup of raw chopped carrots has about 15 mg of carotene, according to the U.S. Department of Agriculture's Nutrient Database, so you'd need to eat half a cup of chopped carrots every day for months, in order to turn to her shade of yellow.
Despite such dramatic outward appearance, carotenemia is a mostly harmless condition and it is often reversible.
Tuna sushi
Sushi lovers beware: eating too much raw tuna can increase your intake of mercury. Large fishes on top of the food chain, such as the prized bluefin tuna, can accumulate methyl mercury in their muscles because they consume many smaller fishes over their lives.
It's difficult to pin down the mercury levels in pieces of sushi, because they can vary depending on the size and species of fish. This makes it difficult to set a definitive cap on sushi consumption.
However, tuna sushi from restaurants tends to have higher mercury levels than supermarket tuna sushi, according to research published in the journal Biology Letters in 2010. Some samples of bigeye tuna or bluefin tuna, which are more common in restaurants, had mercury levels that exceeded or approached levels permissible by regulatory agencies in the U.S., Canada other nations and the World Health Organization, the study showed.
Because mercury can cause severe neurological problems, pregnant women and young children are advised by the Food and Drug Administration and the Environmental Protection Agency to avoid eating too much tuna. According to the agency's 2004 guidelines, others can eat up to 6 ounces (approximately equal to one average meal) of tuna steak per week.
Kombucha Tea
Kombucha is a sugary, black tea fermented by a flat, pancake-like symbiotic culture of bacteria and yeasts called the "Kombucha mushroom." It can be purchased at health food stores or made at home with the starter "mushroom," the beverage is reputed to have immunity-boosting and beneficial effects, but there is very little scientific evidence of these available in current literature.
Although the brew is mostly benign (it usually tastes very acidic, and contains alcohol from the fermentation process), the American Cancer Society has warned that certain Kombucha starter cultures may contain contaminants such as molds and fungi, some of which can cause illness.
There have been reported cases of severe toxic reactions to Kombucha tea. In a recent report published in the Journal of Intensive Care Medicine by physicians at Cedars-Sinai Medical Center in Los Angeles, a 22-year-old male newly diagnosed with HIV became ill within twelve hours of consuming the tea. He was short of breath, his temperature spiked to 103.0 degrees Fahrenheit (39.4 Celsius), and he subsequently became combative and confused, requiring sedation and intubation for airway control.
The Centers for Disease Control and Prevention pointed out that kombucha tea consumed in typical quantities approximately 4 ounces daily might not cause adverse effects in healthy persons. However, those with preexisting health problems or those who drink excessive quantities of the tea should beware.
Coffee
Although some people claim they would cease to function properly without their cup of morning coffee, it's best not to have too many cups. According to the Mayo Clinic, you shouldn't consume more than 500 to 600 milligrams of caffeine a day. A typical, 8-ounce cup of medium roast coffee has about 200 mg of caffeine, a 1-ounce shot of espresso has about 75 mg, an 8 ounce cup of black tea can have 120 mg of caffeine.
Noticeable side effects can occur if you consume more than 600 to 900 mg of caffeine a day, according to the Mayo Clinic, and those include: insomnia, restlessness, nausea, irregular heartbeat, muscle tremors, anxiety and headaches. In fact, too much caffeine can be fatal. According to a case published by Swedish physicians in a 2010 issue of Acta Anaesthesiologica Scandinavica, a 21-year-old woman went into cardiac arrest shortly after consuming about 10,000 mg of caffeine. Although she was resuscitated by ventricular fibrillations a few times, she stopped responding to medication three days later.
Star fruit
Star fruit poisoning was first described in 1980 in Malaysia, where it was found to have a depressive effect on the central nervous system. Although star fruits (also known as carambolas) are not as common in North America, it is widely available in Southeast Asia and South America as fresh fruits, in salads and pickled juice.
This uniquely shaped fruit poses very little risk to healthy people when eaten in normal quantities. However, acute kidney failure has been reported in people with a history of kidney diseases. In a 2006 case report published in the Journal of Nephrology, a patient with underlying chronic kidney disease developed a bad reaction after eating star fruit, which led to rapid deterioration in kidney function and permanent renal injury. In a similar case reported in the Hong Kong Medical Journal in 2009, a 76-year-old woman with chronic renal disease was admitted to the hospital in a state of mental drowsiness and accelerated heart rate after eating two star fruits.
Common symptoms for star fruit intoxication include hiccups (the most common symptom, especially in mild intoxication), vomiting, weakness, insomnia, altered consciousness, convulsions and hypotension. People with a history of kidney illnesses should avoid pure, sour star fruit juice (a popular beverage in Taiwan) and mild, diluted pickled juice in large amounts, especially on an empty stomach.
Water
The conventional guideline of drinking eight glasses of water a day has proven to be a myth. But there is such thing as drinking too much water. Water intoxication occurs when a person drinks so much that the water dilutes the concentration of sodium in the blood, creating an electrolyte imbalance.
Water intoxication, known as hyponatremia, is mostly a risk for endurance athletes. A 2005 article in the New England Journal of Medicine found that 13 percent of 488 runners in the 2002 Boston Marathon developed hyponatremia from drinking too much water. According to the researchers, a relatively simple strategy to reduce that risk would be for runners to weigh themselves before and after training runs, in order to gauge their overall fluid intake and ensure they do not drink too much water during exercise.
An unusual and fatal case of water intoxication occurred in 2007 when a California woman reportedly drank too much water during a "Hold Your Wee for a Wii" radio station contest.
Nutmeg
The light dusting of nutmeg on your eggnog has practically no effects aside from making your beverage more delicious. However, trouble kicks in when the spice is consumed in excessive quantities as a low-cost hallucinogenic drug.
Unpleasant side effects usually appear three to eight hours after ingestion, and can include anxiety, fear, and a feeling of impending doom. According to a case report published in Emergency Medicine Journal in 2005, some people may also experience acute psychotic episodes, detachment from reality and visual hallucinations.
Nutmeg, even in doses as high as 20 to 80 grams of powder, is rarely deadly. There were only two reports of fatal nutmeg overdoses in medical literature. The first was reported in 1908 and involved about 14 grams ingested by an 8-year-old. The second case involved a 55-year-old and was reported in the journal Forensic Science International in 2001. Toxicology tests found traces of myristicin (a compound found in the essential oil of nutmeg) and flunitrazepam (a powerful sedative) in her blood. Her death was likely due to the combined toxic effect of both substances, the report said.
