BARRY'S BOOKS


New book in Dutch

Eet vet word slank

Eet vet word slank gepubliceerd januari 2013

In dit boek lees je o.a.: * heel veel informatie ter bevordering van je gezondheid; * hoe je door de juiste vetten te eten en te drinken kan afvallen; * hoe de overheid en de voedingsindustrie ons, uit financieel belang, verkeerd voorlichten; * dat je van bewerkte vetten ziek kan worden.


Trick and Treat:
How 'healthy eating' is making us ill
Trick and Treat cover

"A great book that shatters so many of the nutritional fantasies and fads of the last twenty years. Read it and prolong your life."
Clarissa Dickson Wright


Natural Health & Weight Loss cover

"NH&WL may be the best non-technical book on diet ever written"
Joel Kauffman, PhD, Professor Emeritus, University of the Sciences, Philadelphia, PA



Animal Fats Don't Cause Breast Cancer




Did you notice how low-carb diets have hit the news in 2003? Wheat farmers in the USA were finding they can't sell their crop as people were giving up eating bread. Potato farmers faced a similar crisis in Britain. And I heard a spokeswoman from the Vegetarian Society admit that 600,000 people had given up on vegetarianism.

The next thing to happen may well be all the people who have taken the 'healthy' advice and put weight on or developed diabetes as a consquence may decide to sue those nutritionists who gave them that bad advice.

During the third week of July, 2003, two studies were published which purported to show that an increasing intake of animal fat increased the risk of breast cancer. It looks like the conventional 'fat is bad for you' nutritionists are stepping up their rearguard action in a vain attempt to prevent this inevitable backlash.

The first was an American study published on 16 July in the Journal of the National Cancer Institute ; the second out on 18 July in the British medical journal, Lancet . Below I have included abstracts from them. Look carefully at them and you will see what the real truth is. I must confess, when I read them both, I was decidedly underwhelmed by the arguments. As the media — and the researchers — tend to hype up their results for maximum impact, I have added comments to each to explain what the figures mean in real terms.

The first study was reported in the American press thus:



Animal Fats Linked to Increased Breast Cancer Risk, Study Finds

July 15 (Bloomberg) — Eating high-fat red meats and dairy products such as cream may increase the risk of breast cancer in pre-menopausal women, according to a study published in tomorrow's issue of the Journal of the National Cancer Institute.

A diet high in animal fat raised the risk by as much as 54 percent, said lead author Eunyoung Cho, a nutrition researcher at Boston's Harvard Medical School and Brigham and Women's Hospital. The eight-year study enrolled 90,000 women aged 26 to 46.

The findings suggest that the Atkins diet and other regimens that encourage people to eat meat to lose weight may harm younger women, Cho said. Her study found no link between breast cancer, which kills about 40,000 people a year in the U.S., and high levels of vegetable fat or animal fat from chicken, turkey or fish, she said in an interview.

"I would not recommend that diet for pre-menopausal women, unless they replace red meat with poultry and fish," Cho said.

Women at the high end of animal fat consumption got 23 percent of all their calories from meats and dairy products, almost twice as much as those who ate the least animal fat. Some researchers believe that a high-fat diet may increase the risk of breast cancer by spurring the body to make estrogen, which can contribute to tumor growth, Cho said.

Now let's look at what the study really revealed:

Eunyoung Cho, Donna Spiegelman, David J. Hunter, Wendy Y. Chen, Meir J. Stampfer, Graham A. Colditz, Walter C. Willett Premenopausal Fat Intake and Risk of Breast Cancer. J Natl Cancer Inst 2003;95:1079-85

Background: International comparisons and case-control studies have suggested a positive relation between dietary fat intake and breast cancer risk, but prospective studies, most of them involving postmenopausal women, have not supported this association. We conducted a prospective analysis of the relation between dietary fat intake and breast cancer risk among premenopausal women enrolled in the Nurses' Health Study II.

Methods: Dietary fat intake and breast cancer risk were assessed among 90 655 premenopausal women aged 26 to 46 years in 1991. Fat intake was assessed with a food-frequency questionnaire at baseline in 1991 and again in 1995. Breast cancers were self-reported and confirmed by review of pathology reports. Multivariable relative risks (RRs) and 95% confidence intervals (CIs) were calculated. All statistical tests were two-sided.

Results: During 8 years of follow-up, 714 women developed incident invasive breast cancer. Relative to women in the lowest quintile of fat intake, women in the highest quintile of intake had a slight increased risk of breast cancer (RR = 1.25, 95% CI = 0.98 to 1.59; Ptrend = .06). The increase was associated with intake of animal fat but not vegetable fat; RRs for the increasing quintiles of animal fat intake were 1.00 (referent), 1.28, 1.37, 1.54, and 1.33 (95% CI = 1.02 to 1.73; Ptrend = .002). Intakes of both saturated and monounsaturated fat were related to modestly elevated breast cancer risk. Among food groups contributing to animal fat, red meat and high-fat dairy foods were each associated with an increased risk of breast cancer.

Conclusions: Intake of animal fat, mainly from red meat and high-fat dairy foods, during premenopausal years is associated with an increased risk of breast cancer.

COMMENT: Now let's look at their figures for animal fats.


Animal fat intake quintile
1
2
3
4
5
P trend
No. of women
17 994
18 150
18 188
18 216
18 106
-
Range of animal fat intake, % of energy
<14
14-16
16-18
18-21
21-46
-
No. of cases of cancer
123
145
151
161
134
-
Median intake animal fat, % of energy
12
15
17
20
23
-
Age-adjusted RR (95% CI)
1.00 (referent)
1.22 (0.96 to 1.55)
1.26 (1.00 to 1.60)
1.38 (1.09 to 1.74)
1.15 (0.90 to 1.47)
.04

COMMENT: Percentage of women who did NOT get breast cancer

99.32
99.20
99.17
99.12
99.25
.04


COMMENT:

If eating animal fat increased the risk of breast cancer, one would expect that the more animal fat is eaten, the more breast cancer there will be. That is clearly not the case. Those eating the most animal fat (5th quintile) have less breast cancer than those eating less (3rd and 4th quintiles). That is the first sign that something is not quite what it should be.
    The second is that the range of findings cuts across 1.0 (below 1.0 indicates benefit; above 1.0 indicates harm; and 1.0 means neither benefit nor harm). This indicates that the figures may not be significant.
    This is then confirmed if one looks at the "P" figure. This is a measure of the likelihood that the final figure HAS been arrived at by accident. The higher the figure, the higher the likelihood that the outcome is an artefact rather than a true finding. A 'P' of 1 is 100% — a certainty that it is an accidental figure — and .01 means a 1% chance that this is an accidental result. Thus a figure less than .01 is usually required to indicate statistical significance; .001 would be highly significant. The P figure for animal fats is higher at .04.

This study uses what is known as a 'data dredge' (see below). And it contradicts all other studies that have gone before which all show that increasing animal fats have a cancer protective effect. It also tries to contradict our entire evolutionary history: cancer has really only 'taken off' in the last couple of centuries, yet we have been eating animal fats for millions of years.

Another thing that is strange about this study is that this group published a paper only 4 months ago in which they were unable to find a breast cancer risk for red meat intake (see abstract below). Interestingly in the new paper above, analysis was not even mentioned. That abstract is below. It refutes the above study.

Holmes MD, Colditz GA, Hunter DJ, Hankinson SE, Rosner B, Speizer FE, Willett WC. Meat, fish and egg intake and risk of breast cancer. Int J Cancer. 2003 Mar 20;104(2):221-7.

Intakes of animal protein, meat, and eggs have been associated with breast cancer incidence and mortality in ecological studies, but data from long-term prospective studies are limited. We therefore examined these relationships in the Nurses' Health Study. We followed 88,647 women for 18 years, with 5 assessments of diet by food frequency questionnaire, cumulatively averaged and updated over time. We calculated the relative risks (RR) and 95% confidence intervals (95% CI) for risk of developing invasive breast cancer, over categories of nutrient and food intake.

During follow-up, 4,107 women developed invasive breast cancer. Compared to the lowest quintile of intake, the RR and 95% CI for the highest quintile of intake were 1.02 (0.92-1.14) for animal protein, 0.93 (0.83-1.05) for red meat and 0.89 (0.79-1.00) for all meat. Results did not differ by menopausal status or family history of breast cancer. We found no evidence that intake of meat or fish during mid-life and later was associated with risk of breast cancer.




The second study was published in Lancet. Again it was hyped up by the media as 'conclusive proof that a high animal fat diet causes breast cancer' but, again, it is nothing like conclusive! Using similar methodology to that which I have applied above, you will see a similar pattern here:

Are imprecise methods obscuring a relation between fat and breast cancer?
Sheila A Bingham, Robert Luben, Ailsa Welch, Nicholas Wareham, Kay-Tee Khaw, Nicholas Day
Lancet 2003; 362: 212-14

Abstract
Pooled analyses of cohort studies show no relation between fat intake and breast-cancer risk. However, food-frequency questionnaire (FFQ) methods used in these studies are prone to measurement error. We assessed diet with an FFQ and a detailed 7-day food diary in 13 070 women between 1993 and 1997. We compared 168 breast-cancer cases incident by 2000 with four matched controls. Risk of breast cancer was associated with saturated-fat intake measured with the food diary (hazard ratio 122 [95% CI 106-140], p=0005, per quintile increase in energy-adjusted fat intake), but not with saturated fat measured with the FFQ (110 [094-129], p=023). Dietary measurement error might explain the absence of a significant association between dietary fat and breast-cancer risk in cohort studies.


COMMENT:

As its title suggests, this study is really looking at the way data are gathered. What it is really saying is "We 'know' that saturated animal fat causes breast cancer, but we can't prove it in trials." (This is, of course, because all trials published so far — and there have been a lot — have found that animal fats do NOT cause breast cancer, only vegetable fats do — but that finding isn't politically correct). So now, this team looked at the way data are gathered to see if they could spin their findings to show what they want to see.

Note that they show a P value of .005 for a food diary, whereas the P for a food frequency questionnaire, the usual way to gather information, is .23. This means that the food diary is very much more reliable.

Now, using this method they studied 25630 men and women to look for effects of fat intake and breast cancer.
    They, too, split fat intakes into quintiles. There were 168 cases of breast cancer between January, 1993 and September, 2002, in participants who had completed both dietary methods. Unfortunately, this study doesn't break them down into how many ate how much fat, as the first study did. However, 168 out of over 25000 in 10 years is not very many on which to base reliable findings. And, again the data show clearly that the ones who ate the most fat had less breast cancer than those who ate less. The numbers with cancer in the two highest intakes (4th and 5th quintiles) was less than the numbers in third.
    So another waste of time!



Here is an example of a Data Dredge from Number Watch , an extremely interesting website if you want to know how scientists use figures to mislead us lesser mortals. It is based on an Italian study that found that if women lived a more 'healthy' life, they would live longer.


Number Watch decided to perform its own study, but not having generous donors to fund a jaunt to Italy, it has to rely on the random number generator in Mathcad. It was easy enough to use the same Trojan numbers, but necessary to make a guess at the number of lifestyle habits and the proportion of women adopting each one. The numbers chosen were fifty habits and a one in ten adoption of each. A set of 50 binomial random numbers was generated (for the cognoscenti by rbinom(50,2800,0.1) ) and another set for the 4000 controls with exactly the same number of habits and probability. The percentage difference was then recorded and ranked, the five at each extreme being used to form the table. The habits were named from the standard SIF hit list. The results were as follows.
Habit % change in risk
Tomatoes -11.355
Jogging -11.354
Green vegetables -10.891
Aubergines -10.223
Olive oil -8.807
Insecticides +8.753
Passive smoking +10.883
Saturated fats +12.128
Alcohol +16.305
Smoking +16.456

Not bad, when you consider that there is no difference in the probabilities in the two populations! Combining the last three observations, we can now announce to the women of the world that by giving up smoking, alcohol and saturated fats they can cut their risk of breast cancer by one third — a similar result to the good professor's at a tiny fraction of the cost.

As you can see, although the parameters were exactly the same for both the 'treatment group' and the 'control group', merely the fact that there were not exactly the same number of people in each group, skewed the figures. And that may be exactly what happened in the two studies above.

Last updated 15 July 2008





Related Articles