Don’t Eat Fruit Bats, and Avoid Algae Blooms!

The peo­ple with the world’s high­est risk of Lou Gehrig’s dis­ease were the Chamor­ro peo­ple, who were the native peo­ple of Guam. These peo­ple also had a high risk of Alzheimer-like demen­tia and dis­or­ders like parkin­son­ism. The prob­lem didn’t seem to be genet­ic or con­ta­gious, and the dis­eases became less com­mon when the pop­u­la­tion became more Amer­i­can­ized after World War II. These facts sug­gest­ed that the prob­lem result­ed from some­thing that the peo­ple had been eat­ing.

The prime sus­pect in this case is a neu­ro­tox­in called BMAA (beta-methy­lamino-L-ala­nine). It’s sim­i­lar to the amino acid ala­nine that your body uses in mak­ing pro­tein. When BMAA was giv­en to rhe­sus macaques, the result­ing dam­age to the ner­vous sys­tem was sim­i­lar to what was hap­pen­ing to the afflict­ed peo­ple on Guam.

The BMAA orig­i­nal­ly came from cyanobac­te­ria. The cyanobac­te­ria are true bac­te­ria, although they are some­times called blue-green algae. The cycad plant, which was an impor­tant food source for the Chamor­ro peo­ple, has a part­ner­ship (sym­bi­ot­ic rela­tion­ship) with cyanobac­te­ria of the genus Nos­toc. The cycads give some sug­ar to the Nos­toc liv­ing on their roots. In return, the Nos­toc con­vert some of the nitro­gen from the atmos­phere into ammo­nia, which the cycad can use as fer­til­iz­er.

Unfor­tu­nate­ly, the Nos­toc also make some BMAA, which is also absorbed by the cycad. The Chamor­ro peo­ple then were exposed to BMAA when they ate seeds from the cycad plant. They got an even big­ger dose of BMAA when they ate fruit bats, because the BMAA had become con­cen­trat­ed in the bats’ bod­ies. This process of con­cen­tra­tion is called bioac­cu­mu­la­tion.

There are two take-home lessons from this sto­ry. The first is that we may need to be care­ful about human expo­sure to cyanobac­te­ria. All types of cyanobac­te­ria but only cyanobac­te­ria pro­duce BMAA. Human beings could be exposed to BMAA as a result of the tox­ic algae blooms that are becom­ing increas­ing­ly com­mon because of fer­til­iz­er runoff. Peo­ple could become exposed to BMAA by drink­ing or swim­ming in con­t­a­m­i­nat­ed water, such as the water in ponds and reser­voirs. They could also be exposed to BMAA through cyanobac­te­ria in foods or sup­ple­ments made from algae.

The sec­ond les­son is that BMAA, like many oth­er tox­ins, becomes more con­cen­trat­ed as you move up the food chain. Fruit bats con­tained more BMAA than the cycad seeds did. Oth­er tox­ins, such as diox­in and mer­cury, also con­cen­trate as you go up the food chain. It’s anoth­er rea­son why it’s bet­ter for us to eat plants, not ani­mals.

Pho­to by Tam­bako the Jaguar

21 thoughts on “Don’t Eat Fruit Bats, and Avoid Algae Blooms!”

  1. Hi, I’m a lit­tle dis­turbed by the way you por­tray a med­ical exper­i­ment involv­ing the inten­tion­al poi­son­ing of mon­keys in a pos­i­tive light. You often do cite cru­el ani­mal stud­ies as being edu­ca­tion­al. Obvi­ous­ly, that was not the only way to learn about BMAA (and it is ques­tion­able to assume the same result in humans), and it was obvi­ous­ly a hor­ri­ble expe­ri­ence for the macaques. Can you write an arti­cle explain­ing your views on ani­mal test­ing?


  2. Hi Frag­gle.
    I think it would be a trag­ic mis­take to ignore the results of any sci­en­tif­i­cal­ly valid study, regard­less of whether one approved of how or why it was done. I often write about the lessons we’ve learned from the con­se­quences of wars or famines. That doesn’t mean I approve of wars or famines.

  3. I real­ly love your site.

    I have been a veg­e­tar­i­an since 1979. Recent­ly, I have made the step towards raw veg­an.

    I love fruit. How­ev­er, I have a few reser­va­tions and am won­der­ing if you could kind­ly help clear up these nag­ging doubts, or direct me to where I could get some answers, please?

    Dr Robert Lustig who appears to be an emi­nent aca­d­e­m­ic and author rais­es the issue of cho­les­terol and oth­er health issues w.r.t. fruc­tose, say­ing that it is not high fat diets that are dan­ger­ous, but diets high in fruc­tose. His book is enti­tled Sug­ar: The Bit­ter Truth.
    Of course, fruit has fruc­tose, and the amount of fibre they con­tain wouldn’t alter that, except to affect the rate of absorp­tion. There is also the aspect that fruc­tose is metabolised dif­fer­ent­ly to sug­ar, that is, that it is metabolised in the liv­er, which could lead to liv­er issues when con­sumed abun­dant­ly, as I sup­pose would be the case in a diet pre­dom­i­nant­ly of fruit.

    The oth­er issue is that of car­bo­hy­drates. Cer­tain research points to high car­bo­hy­drate diets affect­ing cho­les­terol lev­els, in par­tic­u­lar LDL and triglyc­erides. A book in this con­nec­tion is Gary Taubes’ Good Calo­ries, Bad Calo­ries.

    Then of course, there is the glycemic index and glycemic load slant to the argu­ment.

    By eat­ing a lot of fruit, even if the fruit select­ed is low glycemic, hav­ing large quan­ti­ties in one’s diet would nonethe­less ensure that there is a sharp spike in the insulin lev­el by virtue of the glycemic load. In oth­er words, the sheer quan­ti­ty will cause a spike in insulin, which is not only bad for main­tain­ing one’s weight, or los­ing body fat, but high insulin dam­ages cells, and can lead to insulin resistence.

    Please could you help?



  4. Hi Chris:

    Why are you wor­ried about these things? Are you sick or over­weight now? If so, I strong­ly rec­om­mend that you ask a reg­is­tered dietit­ian for dietary advice.

    I can’t give you per­son­al advice, but I can explain some rel­e­vant data. When Chris Voigt ate prac­ti­cal­ly noth­ing but pota­toes for 60 days, he lost 21 pounds and end­ed up with dra­mat­i­cal­ly low­er cho­les­terol and fast­ing blood sug­ar lev­els.
    I think it’s nuts to eat only one food for an extend­ed peri­od, but his pub­lic­i­ty stunt debunks the the­o­ry that high glycemic load foods nec­es­sar­i­ly make you fat, give you high cho­les­terol, or make you dia­bet­ic.

    The fruc­tose in fruit is so dilute that most peo­ple would have to be forcibly fed to get enough fruc­tose from fruit to have seri­ous health prob­lems. On the oth­er hand, you could eas­i­ly end up with trou­ble from eat­ing too much hon­ey or agave syrup or table sug­ar or high-fruc­tose corn syrup, espe­cial­ly if you are adding those things to a fat­ty, high-cho­les­terol diet.

    For com­plete­ness, I should men­tion that some peo­ple have par­tic­u­lar prob­lems with fruc­tose. There’s a rare hered­i­tary dis­ease called fruc­tosemia or hered­i­tary fruc­tose intol­er­ance.

    There’s also an unre­lat­ed con­di­tion called fruc­tose mal­ab­sorp­tion that’s fair­ly com­mon in peo­ple of cen­tral Euro­pean ances­try.

  5. There’s a the­o­ry that algae that links to neu­ro­log­i­cal dis­ease, it because of the tox­ins that it pro­duce that affect­ed the shell­fish that can be digest by human.

  6. After the Nazis invad­ed Nor­way and stole the Nor­we­gian people’s farm ani­mals dur­ing WWII, the inci­dence of new cas­es of mul­ti­ple scle­ro­sis in Nor­way dropped pre­cip­i­tous­ly. Exist­ing cas­es tend­ed to stop pro­gress­ing. That was just one piece of evi­dence sug­gest­ing that eat­ing a fat­ty diet based on ani­mal-source foods is a nec­es­sary cause of mul­ti­ple scle­ro­sis. If you cor­rect the diet, the mul­ti­ple scle­ro­sis stops pro­gress­ing.

  7. I am read­ing your book _Not Trivial_ and want­ed to see what you thought about Dr. Lustig. I’ve watched 3 of his videos recent­ly. His big con­cern is that in processed foods when Dr’s warned about fat, in order to reduce fat and to make food still taste good, food mak­ers start­ed adding a lot of fruc­tose to foods. He didn’t seem to me very con­cerned about fresh fruit. He was very con­vinc­ing. I am inclined to think a bal­anced diet is best, but what that is is debat­able. I try to eat rice, mixed veg­eta­bles, and fresh fruit reg­u­lar­ly. I also eat a lit­tle meat occa­sion­al­ly. I have been unable to alto­geth­er resist choco­late. I have type 2 dia­betes but it is well con­trolled. I also won­der about aspar­tame, which I have read bad things about. I have avoid­ed it alto­geth­er for sev­er­al years (in fact all pop).

  8. Processed foods are gen­er­al­ly devoid of fiber, which is a good rea­son to avoid them. I think that “bal­ance” and “mod­er­a­tion” are dan­ger­ous con­cepts in nutri­tion. As Cald­well Essel­styn point­ed out, “When it comes to low­er­ing cho­les­terol, mod­er­a­tion kills.” Peo­ple use the word “bal­ance” to imply that you should con­tin­ue to eat foods that come from ani­mals. If you have type 2 dia­betes, you might want to con­sid­er going to either Dr. McDougall’s pro­gram or the Rice Diet pro­gram. They can teach you how to become undi­a­bet­ic.

  9. Nixon was moti­vat­ed for polit­i­cal rea­sons (1972) to encour­age high fruc­tose corn syrup.
    Dr. Robert Lustig’s 90 minute video on fruc­tose.

    He says the fruc­tose in fresh fruit is not a prob­lem because of the high­er fiber.
    He seems to think the biggest prob­lem is soft drinks, but does not talk at all about aspar­tame.

    I have also read:
    Sweet­ly Seduced – by NJ Rick­man
    Sui­cide by Sug­ar – by Nan­cy Apple­ton, PhD and G. N. Jacobs

    Also on Aspar­tame.
    Regan was involved: (his appointee to FDA over­turned FDA deci­sion, and lat­er moved to com­pa­ny mak­ing aspar­tame)

    So was Rums­feld: (He was pres­i­dent of com­pa­ny mak­ing aspar­tame)

    I have also read:
    ASPARTAME (NutraSweet*) Is It Safe? By H. J. Roberts, M.D.

    Of course, the involve­ment of Nixon, Regan and Rums­feld does not prove the dan­gers, but does sup­ply motive to sup­press the truth.

  10. There’s a bit of a mis­un­der­stand­ing about sug­ar and fat. The excess sug­ar that peo­ple are get­ting from processed foods such as soft drinks gen­er­al­ly does not turn into fat. Instead, the body burns that avail­able sug­ar right away and then stores the sur­plus fat­ty acids from the food as fat. Although the human body can con­vert sug­ar to fat, that con­ver­sion doesn’t gen­er­al­ly hap­pen to any sig­nif­i­cant degree until the amount of sug­ar that the per­son is eat­ing is greater than the total ener­gy expen­di­ture.

    There’s a huge amount of anti­sug­ar non­sense being spread by the pop­u­lar media. One pop­u­lar the­o­ry is that excess sug­ar con­sump­tion caus­es dia­betes by caus­ing the pan­creas to wear out. Lustig believes that fruc­tose caus­es hyper­ten­sion. Yet when Wal­ter Kemp­n­er taught his patients with malig­nant hyper­ten­sion to eat a diet con­sist­ing of rice, fruit, and sug­ar, their blood pres­sure came down, they lost weight, and their insulin sen­si­tiv­i­ty improved. If Lustig’s the­o­ry that fruc­tose caus­es hyper­ten­sion were cor­rect, then their blood pres­sure would have gone up, not down, wouldn’t it?

    As for aspar­tame, do we have any evi­dence that any par­tic­u­lar health prob­lems sud­den­ly became more com­mon after the intro­duc­tion of aspar­tame?

  11. Accord­ing to Dr. Lustig, (he gives a detailed bio­chem­istry les­son in the 80 minute video U gave a link to) we can only digest glu­cose direct­ly for ener­gy. What we call table sug­ar or sucrose is about 1/2 glu­cose and 1/2 fruc­tose and the same is true of high fruc­tose corn syrup. (they are actu­al­ly larg­er mol­e­cules which break down quick­ly into these.) From what I have been able to learn, starch­es as rice and pota­toes break down close to 100% glu­cose. The fruc­tose must be processed by the liv­er, and caus­es prob­lems like alco­hol. Also one would have to know what Wal­ter Kempner’s patients diets were before his test and/or com­pare to oth­er spe­cif­ic diets.

    Also on aspar­tame:

    Also, my per­son­al notes are at:

  12. I’ve read more on your blog, and you and Dr. Lustig do not real­ly seem that far apart. Some of the facts I cit­ed above I got from Dr. Lustig, but are also on your blog. As for aspar­tame, as a prac­ti­cal mat­ter, I can­not see how it can have any ben­e­fit. Tho only one would be to elim­i­nate sug­ar, but I have stopped all soda pop, and try to avoid too much sug­ar in oth­er sources,
    although I do not do as well as I would like.

  13. Kempner’s patients were eat­ing the stan­dard fat­ty Amer­i­can diet back in the days before there were any drugs for low­er­ing blood pres­sure. His diet wasn’t a “test diet.” It was the stan­dard diet that he rec­om­mend­ed to all his patients over the course of many years. Sad­ly, the Rice Diet pro­gram just closed its doors this month, after 70 years of help­ing peo­ple lose weight and recov­er their health.

  14. The main dif­fer­ence between you and Dr. Lustig is that he finds the main dietary prob­lem to be fruc­tose and you find it to be fat. How­ev­er the main fruc­tose he wants to avoid is from processed foods, which you also say to avoid. He thinks, at least in some cas­es, body fat results from too much fruc­tose. My expe­ri­ence is that as I eat a mod­er­ate amount of sug­ar, my glu­cose lev­el stays OK. Also I I have had my triglyc­erides and cho­les­terol well under con­trol. Twen­ty years ago I had a ter­ri­ble diet. I just didn’t know how to eat. I got way too much of booth sug­ar and fat. My expe­ri­ence is that after one goes past some thresh­old (hard to deter­mine) your body los­es the abil­i­ty to han­dle either of these.

  15. Thanks very much for that link. I am still inclined to believe one can con­sume too much sug­ar (part­ly from my per­son­al diet & glu­cose records) — at least if you are dia­bet­ic. The thing that seems to help my dia­betes most, besides med­i­cine, is con­trol­ling my weight..

  16. Type 2 dia­betes is the body’s attempt to pre­vent fur­ther weight gain on a fat­ten­ing diet. If you add extra calo­ries of any kind to an already fat­ten­ing diet, such as by drink­ing sug­ary sodas, you will make the prob­lem worse. Keep in mind that the high blood sug­ar lev­els are mere­ly an effect of type 2 dia­betes, albeit an effect that can lead to com­pli­ca­tions. The goal in man­ag­ing type 2 dia­betes should be to restore nor­mal sen­si­tiv­i­ty to insulin, not just to con­trol the blood sug­ar lev­els. The com­mon­ly used dietary and med­ical approach­es to man­ag­ing type 2 dia­betes mere­ly focus on con­trol­ling the blood sug­ar, not on restor­ing nor­mal sen­si­tiv­i­ty to insulin. By urg­ing peo­ple to go on low-carb diets, doc­tors are keep­ing their patients’ blood sug­ar more or less under con­trol but keep­ing them dia­bet­ic.

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