The Cholesterol Wars: the Skeptics vs. the Preponderance of Evidence

Most of our major caus­es of death and dis­abil­i­ty in the Unit­ed States today are a direct result of the stan­dard Amer­i­can diet. It would be bad enough if peo­ple knew that their eat­ing habits were endan­ger­ing their health. What’s worse is that peo­ple are harm­ing them­selves unknow­ing­ly, by eat­ing foods that they have been told are good for them and even essen­tial to good health. This tragedy goes on part­ly because peo­ple don’t want to hear bad news about their bad habits. How­ev­er, I think that a major part of the prob­lem is that most Amer­i­cans have had a poor sci­ence edu­ca­tion and most of their doc­tors have had poor train­ing in nutri­tion. As a result, they don’t know how to make sense of the sci­en­tif­ic research that is now so eas­i­ly avail­able to them through the Inter­net. As a result, they are eas­i­ly fooled by peo­ple who call them­selves skep­tics but real­ly should be clas­si­fied as deniers.

In 2007, Dr. Daniel Stein­berg pub­lished The Cho­les­terol Wars: the Skep­tics Vs. the Pre­pon­der­ance of Evi­dence. That book pro­vides an excel­lent cri­tique of the argu­ments put forth by the “cho­les­terol skep­tics,” who are peo­ple who deny the “lipid hypoth­e­sis”: the idea that high lev­els of cho­les­terol are a major causative fac­tor in heart dis­ease. He summed up the prob­lem as fol­lows:

As we recount the advances in knowl­edge that ulti­mate­ly proved the cor­rect­ness of the [lipid] hypoth­e­sis, we will exam­ine the crit­i­cisms offered by the oppo­nents. There were sev­er­al, but per­haps the major dif­fer­ence between the “con­vinced” and the “uncon­vinced” was that the lat­ter were unwill­ing to look at the total­i­ty of the evi­dence, i.e., to eval­u­ate the relat­ed by rel­e­vant sep­a­rate con­tri­bu­tions com­ing from dif­fer­ent sources—from exper­i­men­tal ani­mal stud­ies, from epi­demi­o­log­ic stud­ies, from genet­ic analy­ses, and from clin­i­cal obser­va­tions. Each of these fields, approach­ing the prob­lem from dif­fer­ent direc­tions, con­tributed sol­id evi­dence strong­ly impli­cat­ing hyper­c­ho­les­terolemia as a major causal fac­tor in ath­er­o­scle­ro­sis and its clin­i­cal expres­sion. And they did so well before defin­i­tive clin­i­cal tri­als made the causal con­nec­tion clear and unar­guable. How­ev­er, to the naysay­ers, any per­ceived weak­ness in any one line of evi­dence or any one clin­i­cal tri­al was con­sid­ered suf­fi­cient to jus­ti­fy dis­miss­ing the hypoth­e­sis out of hand—and they were quick to point to any­thing that did not fit. It is true that in assess­ing the valid­i­ty of a deduc­tive hypoth­e­sis (if a then b), even a sin­gle dis­cor­dant obser­va­tion (a and not b) refutes the hypoth­e­sis. Such an uncom­pro­mis­ing stan­dard for refu­ta­tion may be war­rant­ed, say, in the case of basic the­o­ries in physics, but that is not the case in med­ical sci­ence, which is only now inch­ing its way toward mem­ber­ship in the hard sci­ences. In med­i­cine we still deal with sta­tis­ti­cal hypothe­ses (if a then b with some prob­a­bil­i­ty c). Occa­sion­al dis­cor­dant obser­va­tions (a and not b) cer­tain­ly weak­en the pro­posed causal con­nec­tion but do so only with some degree of prob­a­bil­i­ty, not absolute­ly.

not-trivial-front-coverNote: Dr. Stein­berg was com­plain­ing that most peo­ple do not know the dif­fer­ence between a deduc­tive and induc­tive argu­ment. This dif­fer­ence is impor­tant, as I explain in my book Not Triv­ial: How Study­ing the Tra­di­tion­al Lib­er­al Arts Can Set You Free. School­teach­ers in the Unit­ed States have been dis­cour­aged from giv­ing their stu­dents direct train­ing in the clas­si­cal triv­i­um of gram­mar, log­ic, and rhetoric. The neglect of the triv­i­um has had sev­er­al seri­ous con­se­quences. One is poor read­ing com­pre­hen­sion and need­less dif­fi­cul­ty in learn­ing for­eign lan­guages. Anoth­er con­se­quence is that few peo­ple know how to make or inter­pret rea­son­able argu­ments. As a result, they are often unrea­son­able, often with­out real­iz­ing it.

2 thoughts on “The Cholesterol Wars: the Skeptics vs. the Preponderance of Evidence”

  1. The gen­tle­man makes a good point about pre­pon­der­ance of evi­dence.

    This is why it’s dif­fi­cult, well, one rea­son why, to have con­ver­sa­tions about cho­les­terol, or about low-carb diets, etc. There is always some study that fails to sup­port a notion, and the con­ver­sa­tion degrades into study ping-pong.

  2. I think the main rea­son why the con­ver­sa­tions are unpleas­ant is that most of the peo­ple who engage in dis­cus­sions of this sub­ject don’t want to approach truth through a dialec­ti­cal process. They just want to reas­sure them­selves that it’s safe to eat bacon.

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