Monday, June 11, 2012

Replacing saturated fat by unsaturated fat decreases CVD risk. Or maybe not!

Background: Recently, a few systematic reviews were published in which the effect of replacing saturated fats by polyunsaturated fats on coronary heart disease (CHD) was examined (1, 2). Both articles showed that this might lead to a small reduced risk of CHD, but all-cause mortality rates did not change by modifying dietary fats. The authors did not conclude that lowering intakes of saturated fat may reduce CHD risk. And the authors from one of the articles showed that results were strongly biased by potential confounders (2). Last year another systematic review on this topic was published (3). Based on their results, this was the first time that authors adviced to lower intakes of saturated fat in order to reduce risk of cardiovascular diseases...

Friday, March 16, 2012

Red meat increases early mortality risk. At least if you live in the USA. Part 1

Background: This week, the news showed us that red meat consumption decreases lifespan (1, 2). But was this effect caused by the red meat, or because meat eaters had a generally unhealthy lifestyle? The news reports based their conclusion on results from the "Health Professionals Follow up Study" and the "Nurses' Health Study" (3) by Pan et al. 37,698 men and 83,644 women participated in the research. At baseline, participants were asked to complete a food frequency questionnaire. And they were asked to do this again every 4 years. Until now, 8,926 men and 15,000 women died during follow-up (22 years for men and 28 years for women). Men in the highest quintile of red meat consumption had a 37% increased risk of dying within the...

Tuesday, March 6, 2012

Do trends in fat intake correlate to changes in heart disease?

Background: This is based on an article published in The British Journal of Nutrion by 13 scientists (Pedersen et al.) and 3 published letters to the editor in response to the article. More detailed background information can be found in an article I described earlier (1). This part describes the evidence for a link between trends in saturated fat consumption and their correlation to changes in CVD. Pedersen et al (2) state that: There have been substantial reductions in mortality from CVD (cardiovascular diseases) in North America, Western Europe and Australasia over the last 30 years that reflect successful national public health policies to reduce the intake of SFA (saturated fatty acids), in addition to promoting smoking...

Monday, March 5, 2012

Natural fats do not negatively influence cholesterol

Background: In October 2011, the British Journal of Nutrition published a guest editorial by 13 scientists (Pedersen et al). In this article, they explain the importance of reducing saturated fat intake to limit heart disease risk (1). Because I found that the base of their information was scientifically incorrect, I decided to write a so-called "letter to the editor", which was also published (2). This was followed by a response by Pedersen et al (3) and again, by a response from me (4). All responses got published in the British Journal of Nutrition. The articles contain a lot of information, so I decided to go for a stepwise analysis of the contents. Pedersen et al are concerned that saturated fatty acids (SFA) may no longer...

Thursday, March 1, 2012

Heart disease and stroke mortality are highest in countries with low saturated fat consumption

Background: In 1993, Artaud-Wild et al published an article linking per capita intakes of saturated fat to mortality rates from coronary heart disease (CHD) (1). A global analysis was done including data from 40 countries. Figure 1 shows that a strong positive correlation (R = 0.78) was found between a "cholesterol-saturated fat index" and CHD mortality among men. This correlation was similar for the % of energy from saturated fat intake (R = 0.77). Figure 1: Is more recent data available? No articles about this correlation were published since. But in 2008, the British Heart Foundation published the European Cardiovascular Disease Statistics (2). The report included European mortality rates from both CHD and stroke for 1972...

Tuesday, February 28, 2012

Vegans don't live longer than vegetarians or meat eaters

Background: If we take a look at wikipedia (1), we see that both vegetarians and vegans have lower mortality rates from heart disease, compared to regular meat eaters: A 1999 meta-analysis of five studies comparing vegetarian and non-vegetarian mortality rates in Western countries found that the mortality rate due to ischemic heart disease was 26 percent lower among vegans compared to regular meat eaters, but 34 percent lower among lacto-ovo vegetarians (vegetarians that eat dairy products and eggs) and pescetarians (those that eat fish but no other meat). Wikipedia also states that: No significant difference in mortality was found from other causes.This line suggests that both vegetarians and vegans may live longer than regular meat eaters....

Sunday, February 26, 2012

Whole grains may decrease diabetes risk

Background: High calcium intake has been linked to lower risk of diabetes in the past (1), though this association may have been confounded by magnesium intake (2). Likewise, high magnesium intake has also been linked to lower risk of diabetes (3). Whole grains contain phytic acid which has been linked to decreased absorption of magnesium, calcium and other minerals from the gastrointestinal tract (4). The combination of these factors is sometimes used to prove that whole grains are to increase diabetes risk. However, the theory is very simplistic not taking into account other nutrients in whole grains and not taking into account the complexity of the human body. If whole grains are to increase diabetes risk, then it would be expected that...

Saturday, February 25, 2012

Berries do not decrease cancer risk

Background: berries are said to decrease cancer risk. If we google for "berries cancer" we see that pretty much all titles suggest this to be true. These ideas are based on the assumption that berries include several nutrients thought to be healthy, such as vitamins, minerals and polyphenols. But if we take a closer look at the evidence, we see that articles are consistently based on either:-Animal research.-Studies in cell lines.-Nothing. No references are given to back up the claim. If berries are to decrease cancer risk in humans, it would be logical that humans with higher intake of berries have lower cancer risk than humans with lower intake of berries.  Methods: I searched the Pubmed database for prospective (= cohort) studies...

Tuesday, February 21, 2012

Milk does not increase hip fracture risk.

Background: Milk intake has been linked to higher risk of bone fractures. If we google the following combination of search words "milk bone fractures women", we see several titles stating that milk may cause osteoporosis/bone fractures. Or titles with "myths about milk". Did past studies truly show that milk increases risk of bone fractures? The links found by google consistently refer to the same scientific article (1). In a 12-year follow-up study, the group of women with the highest intakes of milk, were said to have had a 45% increased risk of hip fracture. Table 1: Table 1 shows effects as described in the full text of the article. We see a Relative Risk (RR) of 1.45 (95% CI = 0.87-2.43; P = 0.22) for women consuming 2 or more glasses...

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