The hypoglycin inhibits both gluconeogenesis and oxidation of fatty acids, preventing the body from using fat or protein for energy. So once their glycogen is used up they're screwed.
It's fascinating.
Does that mean a person in nutritional ketosis could die... ?
Background for others: Most people in keto are running on mostly fatty acids and some ketones (for the things that can't use fatty acids) and a small amount of glucose from gluconeogenesis for the obligate glucose tissues (retina, small percentage of brain, etc).
If you take away the ability to use fatty acids then you have to run off ketones, which should work, but I don't know if the body can make enough (and maybe that is impacted too?). And if your body is using gluconeogenesis to make your essential glucose from protein, and that is inhibited, I would think those tissues would be in trouble (its called essential glucose for a reason).
Probably not. The study covers this in more detail than any of the articles, but malnutrition was the second biggest factor in the deaths.
In most cases of sickness (and nearly all cases of death), the lychee was the bulk of the food eaten by the child. The children were already somewhat hypoglycemic because they weren't eating much, and due to their diet weren't ketogenic (minimal fat or protein in their diet). When the hypoglycin blocked the oxidation of the minimal fatty acids and protein in these children, they eventually ran out of usable glucose, resulting in seizures.
For someone who is merely ketogenic, the hypoglycin would block some but not all of the oxidation of fatty acids, and [edit] generally would not effect the liver production of glucose from glycogen. The amount of dietary fats/proteins in a ketogenic diet would overcome the effect of the hypoglycin, and someone on a normal non-ketogenic diet might not even feel any symptoms due to the body's heavier reliance on the liver-glucose pathway.
You realize I am asking about the effects of someone in nutritional ketosis who is getting a lot of hypoglycin lychee right? Of course I am not saying there is anything wrong with nutritional ketosis itself.
Can confirm as I am from Bihar, India, children eat lots of lychees in the season (also lots of mangoes), even many adults eat just lychee the whole day without any other meal. Seizures were considered as being possessed by demon which explains lack of research and delay in this discovery.
I'm from Jamaica, and grew up eating lots of lychees as well. Never had any problems. Only ate them ripe. I haven't had fresh lychees in years though, mostly now buying the canned ones in syrup from China.
The owners of lychee trees, however, had tons of issues. It's such a loved fruit that if you had such a tree, it was pretty much guaranteed that praedial thieves would strike. It got so bad that I remember one nurse in the community cutting down her tree when the sight of strange men roaming her yard became too much.
It's not very common to eat the unripe litchis though. But children do eat these unripe here and there. As in while running around in those orchards mostly playfully or stealing for fun and taste. We usually eat only ripe ones. I am from the same place as the parent commenter. They taste really bad unripe.
No, litchi orchards are usually sold well before they ripe and people protect it. So most of the litchi is consumed after it's ripe and from the market unless someone has their own orchard.
Malnourished children eating a fruit (lychee) without any previous meal could get poisoned and have a intense decrease in blood sugar levels.
That make me wonders on how many religious practices, superstitions, etc., still exists in modern cultures, transmitted mouth-to-mouth, due to some misunderstanding of the true mechanisms of some occurrence in the past?
I can easily see that a "children can't eat fruits without eating some cereal" could have come as religious belief, from a long past. And it would be effective for hundreds of children.
Kosher food could be a pre-modern public health campaign. Trichinosis is a dangerous parasite found in pork (https://en.wikipedia.org/wiki/Trichinosis) and shellfish have their own dangers.
PG wrote about how he considers many religions to have a culturally-evolutionarily useful bit ('don't eat tainted pork' over time will increase your economic growth) and a viral one, which perpetuates and reinforces the belief.
Historically both pigs and dogs were seen as unclean in the middle east because they roamed the streets eating whatever they could find, which included human waste. Cities used to be pretty dirty. Roman started ranching pigs and shipping them to cities, as the latin folk were really into pork. This solved a lot of the disease problem, as do sewer systems and the like. So if basic precautions are taken against disease, pork is not worse than any other meat.
I know there was an HN article about this, but I can't find it.
I don't know. But I don't think too many other omnivores were usually eaten: cows, chickens, sheep, even horses are all herbivores.
To a larger point, the imprecision of the rule would have been dictated both by customs and limitations in knowledge of the time: culture inasmuch as there would be no need to restrict eating omnivores that nobody ate anyway, and knowledge would dictate how precise you could be while still being safe: we now know that pork is ok to eat, but only because we have the tools to reliably determine whether pork is tainted, and build processes and supply chains that minimize that. For civilizations that didn't yet have that insight, much safer to avoid the whole thing.
Good point... I forgot they'll eat just about anything, including eggs. You don't want to feed them brunch scraps, otherwise they may start poking at unharvested eggs sitting around.
In some cases it's also plainly about animal ethics - "don't boil the calf in the mother's milk" - which tends to be a strong focus when you live with the animals you eat; cf. essentially all indigenous people (as well as Islam and Judaism) who have religious seremonies attached to slaughter, and believe this reduces animal suffering (also in Islam and Judaism).
The Chinese also have a superstition about never drinking anything 'cold'. They have to boil everything first, which was definitely good in ancient times and in places with bad water purification; but it has also led to strange things in the modern era such serving Coke hot.
Coke isn't served hot in China. It's served without refrigeration. Same as Europe.
I would also argue that boiling water still has its place in China. Not every country has the luxury of tap water that wouldn't kill you (except Flint...).
Even if the Chinese have a preference of cold vs warm water, they prefer warm.
It depends on the province, the city, and generation of people. Sure this doesn't happen in Shanghai or even Beijing, but China isn't just Shanghai and Beijing.
The article clearly states that these are "healthy" children who were "uninterested" in eating meals when they consume lychee. I don't see the word "malnourished" or "religious practices" mentioned anywhere in the article.
1 - malnourished: "The children's age and state of nourishment were also factors."
2 - religious practices: I don't say that this was said in the article. I'm conjecturing that "religious practices" could arise, in the past, when people could relate, for example, that children eating those fruits could fall ill, and then could create some religious practice about it.
actually it's exactly the opposite of what you think.
lychee is a relatively new fruit in this region/country, and there wasn't enough transmission over this short period to establish traditions/practices around it.
Hum, let me explain a bit. I understood that it's a new fruit in the region, and seems that even the local population wasn't considering relations between the fruit and the illness. And, exactly because of that, it made me think about how things were in the past.
In other words, given enough time without attention and information and so on, would a new belief arise in that population, one strong enough that would prevent kids from eating the fruit? And few of those who eat them anyway would perish, reinforcing the "tradition" that it was a cursed fruit (or something like that) ?
Of course, if you consider that the same constraints that were present 3,000 years ago still persists: lack of a good knowledge about chemicals and biology and how the human body behaves.
One of the saddest parts of this story is that decades of confusion could have been ended by checking glucose levels in these children at the hospital. This is a basic standard of care but seems like Bihar is so underprovisioned that even this simple step doesn't happen.
> One of the saddest parts of this story is that decades of confusion could have been ended by checking glucose levels in these children at the hospital. This is a basic standard of care but seems like Bihar is so underprovisioned that even this simple step doesn't happen.
It probably did happen, but we're talking about children who are already malnourished to begin with. Establishing a specific food as the cause of their low glucose levels as opposed to the effects of malnutrition is not as easy as simply checking for their glucose levels.
This situation is easily distinguishable from hypoglycemia from starvation - the latter unlikely to happen in non-diabetic children who spent the day eating sweet fruit. Checking basic labs such as a blood glucose fingerstick - as would have happened at a properly provisioned hospital - would not identify the specific fruit but it may well have prevented these kids from dying, as the treatment is just to give sugar.
I'm amazed at the amount of learning that people have to do in order to survive off the flora in a new location. We're mostly spoiled in the modern world by how much the plants we eat are transparent in the preparation needed to eat them.
Being able to come into some new biome, figure out through trial and error what can be eaten when and how, and then transmitting that information reliably to the next generation is what let humans spread all over this planet.
I highly recommend the book The Secret of Our Success covering this and several other topics.
> "A study by the Indian Council of Medical Research concluded that a toxin from kasaundhi trees, being transmitted to humans through insects, caused the disease. The trees were cut and the disease subsided. Litchi trees and mosquitoes present in the region should be studied for this disease," suggested Shah.
Growing up in another country where lychees are commonly eaten, most people were already informed about the fruit's ability to cause hypoglycemia. I remember being told off by parents and older relatives on having too many lychees between meals but again I never heard of any cases of death either.
A casual search on the causative agent (hypoglycin) suggest its presence and mode of action has been well studied since the 1970s, and I wonder why this connection has not been made sooner.
The researchers said the lychee's potential toxic effects were noted in ancient literature from China, where the fruit originates, however the commercial lychee industry in India is relatively young and has expanded quickly.
"This knowledge has been slow to reach certain parts of Asia where the so-called mysterious lychee disease has been attributed to various causes (fruit colouring, heat stroke) in Bihar, India, to an unidentified pesticide in north-west Bangladesh and, after an exhaustive negative virological search, to a yet-to-be-discovered neurotropic virus in northeast Vietnam," Professor Peter Spencer and Dr Valerie Palmer wrote in a Lancet paper discussing the research.
"Fortunately, the high cost of these imported fruits and the likelihood that would be eaten in small quantities by well-nourished consumers, suggests there is little reason for concern in the USA,"
Interesting. As a kid my only experience with Lychees was the canned variety (often found as a desert at Chinese restaurants).
But now days, fresh ones are pretty common, and you can often buy them really cheaply at London fruit stalls: I bought a big 2kg box for £4 recently! Very tasty and we felt no ill-effects despite gorging ourselves on them.
When I was young I was always told not to eat too much otherwise I'd get sick. I always thought it was some old folklore or old wives tale. I asked my dad tonight what he knows about eating too much lychee in regards of getting sick. Off that bat he told me it messed up your sugar level and you can die.
He said he knew it when he was young. I was amazed that my dad, as an impoverished and uneducated boy in China would know this. A lot of people easily discount Traditional Chinese Medicine as anecdote, but somethings should be investigated scientifically (I'm not going to get in an argument here about TCM, but those are my thoughts).
He also mentioned if you soak lychee in salt water you can eat more of it - I would be curious what the scientific backing is, if there is any at all.
And that's another good discussion, on how old knowledge attracts attention from pharma companies and some try to earn patents and all sort of protections from those "new products".
I read sometime ago about India (?) releasing lots of ancient documentation about old medicines, as a knowledge base, exactly to protect the population from those kind of problems.
"Tu was appointed director of Project 523 in 1969, and rather than sift through modern chemicals for a treatment, she scanned ancient Chinese texts for possible herbal remedies for malaria. The earliest description for the parasitic blood disorder comes from Chinese medical texts dating to 2,700 BCE. She found one promising candidate in a 2,000-year-old document that described how sweet wormwood (Artemisia annua) could heal malaria."
> The researchers also said there were now studies looking at how to put the lychee's glucose-lowering properties to good use in treating metabolic syndrome.
It's a misunderstanding by the journalist, since other articles and the study itself expressly stated that the researchers concluded that lychee would probably not be useful for diabetics because it doesn't address the correct glucose pathway, i.e., the liver, from which most blood glucose is generated. Fatty acid oxidation is the secondary pathway for glucose generation in the body and generally isn't responsible for blood sugar spikes.
I understood that Lychee contains a chemical that prevents the body from "burning" fat and protein.
This would be bad for diabetics as low glucose levels can't be helped by burning fat.
And it's the opposite what dieters want, because fat doesn't burn.
I got the impression that the symptoms of the sick/dead children were not unlike a low glucose shock from diabetes once the sugar from the fruit had been consumed.
Perhaps there are other medical uses, but not these two cases.
Sorry for being too Western. I think of Lychee's something as a rarity and a delicacy but I can find them in Chinatown.
When I was in mainland China, near Guangzhou, I remember a woman trying to sell me lychees by the pound -- or whatever unit of measure -- if only I could understand the price she had wanted.
If I understand correctly, these are children from impoverished regions, who only eat Lychees? and they get a type of food poisoning?
Living aside children - in India, it is customary to do "fasting" on auspicious days where people just eat fruits and nothing else. In Bihar in particular - during Chhath (https://en.wikipedia.org/wiki/Chhath) women eat nothing but fruits and drink water.
Most likely it's a vulnerable population and also one that has trouble making it to adulthood for a variety of reasons. It may also be that the researchers were specifically looking at kids and didn't expand the study to cover adults.
Please stop posting uncivilly like this. We've asked you several times before, and eventually we have to ban accounts that refuse to follow the guidelines.
I don't think many would object if all dogs could learn to poop in toilets. So even in the case of dogs it would be preferable if they didn't do it outside.
"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity."
"I did something, and it would be valuable to me if people knew about it (or –less frequently– it would be valuable to the world if people knew about it)."
"Let me see who I can spam about this."
"Oh look. Here are 100 people that have written something about health. Let me send them a pitch that makes this seem mysterious and newsworthy"
Overworked reporter: "Oh man. I need to get a story in or my editor will yell at me. I wonder what I should write about?"
(1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4412228/
(2) https://en.m.wikipedia.org/wiki/Hypoglycin_A