Sunday, December 1, 2013

The Anti-Coronary Club

Studies Associated with the Trial

The Anti-Coronary Club; Including a Discussion of the Effects of a Prudent Diet on the Serum Cholesterol Level of Middle-Aged Men (1959) [1]
The Anti-Coronary Club. The first four years (1963) [2] (no access)
Summary of the Research Activities of the Anti-Coronary Club (1966) [3]
The anti-coronary club: a dietary approach to the prevention of coronary heart disease-a seven-year report (1966) [4]
Effect of the Anti-Coronary Club Program on Coronary Heart Disease Risk-Factor Status (1966) [5]
The Anti-Coronary Club: 1957 to 1972 (1980) [6] 

Phase 1 

The Anti-Coronary Club began in 1957 and initially tested whether a ‘prudent diet’ could lower cholesterol levels and whether a group of male volunteers, aged 40-59, could stick to the diet. 

The prudent diet was: 

  • Low fat animal protein at each meal, with fish or seafood at least five times per week.  Also to use low fat dairy rather than full fat (this translated into 130-150 grams of protein per day)
  • High linoleic acid oils or margarines for cooking, plus an ounce of corn oil daily
  • Avoiding butter, partially hydrogenated margarine and shortenings, and foods containing a lot of them (cakes, pastries) 
  • “Balance your diet by consuming adequate amounts of bread, cereals, nuts, vegetables, and fruits” [1] 

79 of the 86 men continued for at least six months and unsurprisingly, the average cholesterol levels decreased from 251 mg/dl to 222 mg/dl after 6 months, with greater effect in those people who had higher cholesterol at baseline.  So the first phase was seen as successful and they moved to phase 2 [1] 

Phase 2: Participants and Diets

They then got extra people to be in the experimental group (n = 814) and made a control group (n =463).  There were significant differences between the groups at baseline as the experimental group had higher rates of obesity (55.6% vs. 46.7%) and hypertension (23.3% vs. 11.7%), a higher proportion of people aged 50-59 (71.4% vs. 49.0%) and slightly higher cholesterol. 

The prudent diet is this study was: 

“Beef, mutton, or pork are limited to four meals per week, with the remaining meals comprised of poultry and fish, the latter consumed a minimum of four meals weekly. Butter and hydrogenated shortenings are replaced by high P/S ratio margarines and a minimum of one ounce of vegetable oil daily. Ice cream and hard cheeses are avoided. The diet contains about 30 to 33 per cent of total calories as fat with a ratio of polyunsaturated to saturated fatty acids of 1.25-1.50 to 1.20.  The overweight subjects were placed on a diet averaging 1,600 calories and containing 19 per cent of the total calories as fat. When weight reduction was completed, this diet was changed to the standard study diet by the addition of one ounce of vegetable oil plus additional calories when needed from bread, nuts, fruits, and vegetables.” [4] 

Phase 2: Results 

Some of the experimental group no longer visited the clinic every 5 weeks for review sessions, but did have an annual check-up.  These people were considered to have inactive status.  In no case was the onset of a new coronary disease event involved in the shift of a subject to inactive status”. 

Average cholesterol levels decreased in the experimental group from 259.7 mg/dl to 225.8 mg/dl after 5 years.  The experimental group also decreased their rates of obesity and hypertension [5] 

The active experimental group, and even the inactive experimental group, had fewer cardiovascular events than the control group 

Active Experimental Group
Inactive Experimental Group
Control
Group
Number of Subjects
814
290
463
Years of Experience
2367
1482
1224
Confirmed new events
8
8
12
Incidence per 100,000 person-years of experience
339
540
980
[4] 

But mortality was the opposite: 

Of the people who had cardiovascular events: 3/8 died from cardiovascular disease in the active experimental group and another died of other causes, 5/8 died from cardiovascular disease in the inactive experimental group, while in the control group none of the 12 died from cardiovascular disease [5] 

Of the people who didn’t have a cardiovascular event: there were 18 deaths from other causes in the combined experimental group (active and inactive experimental groups, unfortunately they didn’t differentiate), but only 6 in the control group [5]. 

You can then sum these together to get total mortality: 

Combined Experimental Group
Control
Group
Number of Subjects
814
463
Total Mortality
27
6
Mortality (%)
3.32
1.30

The differences in cardiovascular events were significant, but I don’t know whether the differences in cardiovascular mortality, other mortality or total mortality are significant or not. 

It’s interesting that the control group had more cardiovascular events yet none of them were fatal.  Because of the small number of events and death, some of that could very easily be random chance, but this is somewhat consistent with the Rose Corn Oil Trial, where the control group also had a lower proportion of fatal to non-fatal cardiovascular events, though just not as extreme as this study. 

Neither the Cochrane, Mozzaffarian nor Ramsden meta-analyses included the anti-coronary club, and for good reason: the trial was multifactorial.  It didn’t just replace SFA for PUFA, but also manipulated several other variables [4]: 

  • At least four meals with fish per week
  • Hydrogenated shortenings replaced with margarines
  • Weight loss diets for those who were overweight
  • A possible emphasis on whole plant foods 

Since these four changes are likely to be beneficial it confounds the data on cardiovascular events, while making the data on mortality look even worse for the idea that we should replace SFA with PUFA.

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