Grapefruit is weird for many reasons. It was discovered in a land far away from its place of origin. Science is not clear exactly how it was generated, although they believe it was a cross between pomelo and orange. It is not related to grapes, and unlike many other foods, it can majorly disrupt a variety of pharmaceuticals we commonly use today.
Please remember I am just a cook, not a scientist, medical doctor, nutritionist nor dietitian. So speak with your medical expert before making any changes to your diets, and do not make any change based on my posts.
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Citrus History
Citrus in Asia
The ASHS Journal writes that the 3 edible ancestral species of the commercial citrus types are citron (C. medica), pummelo (C. maxima), and mandarin (C. reticulata). But papeda citrus family should be added as a citrus ancestor, the family includies the Ichang lemon, yuzu, kaffir lime, kabosu, and sudachi; all of which were considered less commercial due to their slow growth and bitterness.
Fossil records suggest that the Citrus genus dates back ~7 million years ago, and originated somewhere in the Himalayas (1), before spreading throughout Southeast Asia. From Southeast Asia, and of course MUCH later, citrus took various paths through Asia where they were appreciated and bred into variations we celebrate today. Eventually it spread to the Western world.
Citron (highly pithy fingered lemons) was the first citrus to spread west, through Persia and the Southern Levant, and from there it smoothly moved to the western Mediterranean. The lemon (C. limon) was the second citrus species introduced to the Mediterranean. Followed much later by the sour orange (C. aurantium), lime (C. aurantifolia), and pomelo (C. maxima) after the Islamic conquest. Sweet orange (C. sinesis), again much later, via trade routes established by the Genoese, and again later on by the Portuguese. The mandarin (C. reticulata) reached the Mediterranean only in the early 19th century.
Grapefruit in the Americas
Interestingly, Spain violently invaded Barbados and enslaved many Arawak and Caribbean people, and at the same time also brought oranges and pomelos to the island in the mid-16th Century. The plants thrived and developed on their own, including sharing their DNA (1). Then much of the rest of the 16th Century the island was left alone. Later, Europeans essentially came back and rediscovered the citrus trees ~1750s and saw the new grapefruit which is the only citrus fruit that is acknowledged to have originated in the Americas.
- But citrus naturally hybridizes, whenever two varieties are planted near each other.
- Grapefruits have fragile genomes and are prone to natural and completely spontaneous mutations.
So somehow a couple of trees got together and created the grapefruit in Barbados. Later, in the 1820s, Frenchman Odet Philippe is generally credited with bringing the grapefruit to the American mainland (USA).
Grapefruit Name Mystery
The LibraryofCongress notes that grapefruits were named because of the way they grow, in clusters reminiscent of grapes. However, others write that a Dutch physician Woute Schouden, in 1664, visited Barbados and described a citrus he tasted as “tasting like unripe grapes.” Or perhaps, back in 1814, a British plantation and slave owner John Lunan from Jamaica, reportedly stated that a fruit was named “on account of its resemblance in flavour to the grape.” What is so strange is that at that time there were no grapes in Barbados. Bottom line is no one is sure on why it has the name it does.
Grapefruit Origin
AtlasObscura: The history of citrus fruits are commonly understood to have started ~6M years ago. However, grapefruit is the one citrus that came from the Americas, but its history is cloudy, despite being recently found.
Whatever was the first citrus, at some point it split into different species, including the very important base trio of citron, pomelo, and mandarin.
- Mix certain pomelos and mandarins = sour oranges.
- Mix sour orange and citron = lemon.
- Mix pomelo and mandarin = sweet orange.
- Mix pomelo or shaddock and a sweet orange = grapefruit.
Wikipedia: The grapefruit is a subtropical citrus tree known for its relatively large, sour to semi-sweet, somewhat bitter fruit. The interior flesh is segmented and varies in color from pale yellow to dark pink. Grapefruit is a citrus hybrid originating in Barbados most likely in the mid-1600s.
Types of Grapefruit
There are now over 20 varieties of grapefruit grown in the USA.
Oro Blanco
This grapefruit was created in 1958, and is also known as “white gold.” It is a later cross between a pomelo and a white grapefruit with bright green to lemon-yellow skin, a thick rind, and sweet flesh with limited bitterness.
Pink
Folks consider the pink grapefruit as the most palatable variety for its tang is mild and sweet.
Red
AtlasObscura writes Grapefruit, though, is wild, and wants to remain wild. In 1910, one of Atwood’s workers discovered that one tree was producing pink grapefruits; until then, Florida grapefruits had all been yellow-white on the inside. It became a huge success, leading to the patenting of the Ruby Red grapefruit in 1929.
A budsport mutation from ‘Thompson’ was discovered in Texas in 1929 and patented in 1934. It became a significant commercial cultivar worldwide wherever grapefruit was cultivated (Saunt, 2000). ‘Ruby Red’ is the premier cultivar in Florida, with about 25,700 acres of bearing trees as of 2016 (USDA, 2017a). The fruit has very few seeds; the flesh has more pigmentation than ‘Thompson’, and the peel has a reddish blush. The internal fruit quality is like ‘Marsh’ except for pigmentation pattern (Saunt, 2000) (Fig. 7C). ‘Redblush’ grapefruit also originated as a natural mutant from ‘Thompson’ in 1929, but it did not attain the popularity of ‘Ruby Red’.
White
This grapefruit has a creamy yellow skin and is the least sweet, even though it contains as much sugar as the red. But is described as having a vibrant aroma. White grapefruit juice is a good cocktail mixer for the acidity and subtly bitter flavor of the juice blend well with tropical, fruity drinks.
When first discovered in the West Indies, white grapefruits had a bitter-sour flavor. Thus they were pretty much ignored in its origin country and even when introduced to the USA in the 19th century. Eventually, as citrus tends to do, white grapefruits produced a spontaneous, pink-fleshed fruit that became the dominant commercial variety.
Currently, citrus breeders have sought to create new white grapefruit varieties with improved flavor. The most popular, even though also rare, are Marsh, Duncan, Oro Blanco, and Melogold.
Why Grapefruit is Healthy
In short, grapefruit has been studied and exhibits very positive health benefits. They are considered to have anti-oxidative, anti-inflammatory, anti-proliferative, anti-cancer, bone health, and neuroprotective aspects.
- WebMD: It’s the only citrus fruit native to the Americas. There are over 20 varieties of grapefruit grown in the United States. They are large, bright yellow, and grow in bunches like grapes do — but unlike grapes, grapefruit grows on trees rather than vines.
- JohnHopkins: one whole, medium grapefruit provides you with 100% of your daily requirement for vitamin C, a powerful antioxidant that is great for your immune system and can help you fight off viruses and bacteria that can cause disease.
- Health: Eating one grapefruit daily may help lower LDL, or “bad,” cholesterol. Research has found that overweight adults who eat half of a red grapefruit with each meal (three times a day) may lower their “bad” cholesterol by almost 12 milligrams per decilitre and their total cholesterol by 19 milligrams per decilitre.
- HealthLine: researchers claim that including fiber and antioxidant-rich fruits like grapefruit as part of a healthy diet helps protect against conditions like heart disease and stroke.
Why Grapefruit is Dangerous
TheAtlantic is clear on answering this question: It raises the level of dozens of FDA-approved medications in the body, and for a select few drugs, the amplification can be potent enough to trigger a life-threatening overdose. They further go on to say that no one can agree on exactly how much the world should worry about this bittersweet treat whose chemical properties scientists still don’t fully understand (2, 3).
Grapefruit has the ability to bind enzymes, and can causes certain medications to pass too much and too quickly from the gut to the bloodstream. Furanocoumarins and flavanones are the major compounds in grapefruit identified as responsible in these drug interactions (4).
Digestion and the stomach processes are a very complicated set of biologic and chemical interactions that are way beyond my scientific level as I am just a cook. But I have read up on this and will try below to make one aspect of the problem obvious:
- Whatever we put in our mouths, food or medicine, goes through a gauntlet of physical machinations and chemical run-ins throughout our digestive system.
- Our bodies (mainly the liver and small intestines) creates cytochrome P450 (5), which is a group of super enzymes that do a lot, but for this discussion they coverts certain consumed substances into an inactive state.
- Pharmacies know this, so formulate drugs with this action in mind. For example, they think if you need a 10% dose of a drug, and I know those enzymes will knock out 90%, then the tablet you take will have 100%.
- Grapefruit, has furanocoumarins (6) to protect itself from fungal infections, but those chemicals also incapacitate cytochrome P450 enzymes.
- Our bodies will produce new cytochrome P450, however it takes up to 12 hours.
- During that time, instead of getting, say 10% of the drug the pharmacists calculated, you wind up with 100% and are effectively overdosing.
- It does not take much, ~1C of grapefruit can be enough.
The Drugs vs Grapefruit Issues
This list comes from NHS-UK, MedicalNewsToday, and the FDA. It is a list of drugs for which grapefruit is contraindicated.
- Anti-coagulants (Warfarin)
- Anti-platelets (Clopidogrel and Ticagrelor)
- Amphetamines (Adderall and Ritalin)
- Anti-anxiety SSRIs (Zoloft and Paxil)
- Benzodiazepines (Xanax, Klonopin, and Valium)
- Calcium channel blockers (Prilosec, Amlodipine, Felodipine, Lacidipine, Lercanidipine, Nicardipine, Nifedipine, Nimodipine, and Verapamil)
- Erectile-dysfunction drugs (Cialis and Viagra)
- Immunosuppressants (Ciclosporin, Sirolimus and tacrolimus)
- Statins (Simvastatin and Atorvastatin, Lipitor and Crestor)
- Various over-the-counter meds (Tylenol, Allegra)
- And many more.
Hope this was helpful, it certainly taught me some things, including that we should all review the medications we are taking to see if grapefruit is contraindicated.
—Patty
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