Category Archives: Heart Health

Eating Saturated Fat Contributes To Heart Disease: No Evidence?

SaturatedFatsADAMI think there is a lot of evidence implicating saturated fat in disease. However, there’s a new study which is raising doubt as to the effect of saturated fat on heart disease:

Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis, Annals of Internal Medicine, 18 March 2014

The New York Times reported on it yesterday:
Study Questions Fat and Heart Disease Link

Someone had anonymously linked the New York Times article on my blog. They made no comment.

It’s a meta-analysis with, the authors admit, “potential biases from preferential publication and selective reporting.” Here’s some data:

In observational studies, when the top and bottom thirds of baseline dietary fatty acid intake were compared, relative risks (RRs) for coronary disease were:

1.02 (95% CI, 0.97 to 1.07) for saturated
0.99 (CI, 0.89 to 1.09) for monounsaturated
0.93 (CI, 0.84 to 1.02) for long-chain ω-3 polyunsaturated
1.01 (CI, 0.96 to 1.07) for ω-6 polyunsaturated
1.16 (CI, 1.06 to 1.27) for trans fatty acids

For circulating fatty acids, RRs were:

1.06 (CI, 0.86 to 1.30)
1.06 (CI, 0.97 to 1.17)
0.84 (CI, 0.63 to 1.11)
0.94 (CI, 0.84 to 1.06)
1.05 (CI, 0.76 to 1.44)

In randomized, controlled trials (RCTs), RRs were:

0.97 (CI, 0.69 to 1.36) for α-linolenic
0.94 (CI, 0.86 to 1.03) for long-chain ω-3 polyunsaturated
0.89 (CI, 0.71 to 1.12) for ω-6 polyunsaturated fatty acid supplementations

Note that circulating trans fatty acids had almost the same RR as saturated fat, in fact, trans fats trended more protective? Note also that in RCTs, omega-6 was more protective than omega-3. There is a lot of inconclusiveness here.

These are effects relative to cardiovascular disease (CVD). They did not look at diabetes, arthritis, cancer, or other inflammatory-based diseases. Even if it is true that saturated fat has no impact on CVD, it has been shown to increase the risk for other chronic diseases.

It’s conclusion:

“Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.”

“Not clearly.” Does that remind you of anything? Why did this study get published at all? Recall this study:

Long Term Toxicity Of A Roundup Herbicide And A Roundup-Tolerant Genetically Modified Maize, Food and Chemical Toxicology (FTC), 19 September 2012.

It found more breast cancer, liver and kidney damage in rats fed GMOs.

The publisher was hounded by industry groups like Monsanto to retract it. He resisted for a year, defending it!, then gave in saying:

“Unequivocally, the Editor-in-Chief found no evidence of fraud or intentional misrepresentation of the data. … Ultimately, the results presented (while not incorrect) are inconclusive.”

It was retracted, not because it was incorrect, but because it was “inconclusive.” This present study is also inconclusive. The authors admit as much. Shall we expect it to be retracted? Can you think of any industry that would benefit by keeping this study circulating? Industry doesn’t have to combat science, all they have to do is plant seeds of doubt, and they’ve won.

________Here’s yet another reason why I believe saturated fat contributes to the development of chronic diseases. It was buried in the comments on the New York Times article:

“The results of reducing animal fat consumption in Finland led to greatly reduced cardiovascular disease rates.” -wbgrant

Fat and Heart Disease: Yes We Can Make a Change – The Case of North Karelia (Finland), Annals of Nutrition and Metabolism, July 2009

“The combined efforts of all stakeholders have greatly helped people to reduce the intake of saturated fat and to replace this with unsaturated fat. This has been associated with an improved quality of the dietary fat (e.g. in 1972, over 90% of the population used butter on their bread compared to <5% at present) and a remarkable reduction in blood cholesterol levels. It has led to a 80% reduction in annual CVD mortality rates among the working aged population, to a major increase in life expectancy and to major improvements in functional capacity and health.

There is strong medical evidence that CVD (like many other chronic diseases) is preventable or could be delayed to a more advanced age. A population-based prevention programme is the most cost-effective way and in many cases the only affordable option for major public health improvements. To prevent CVD and to promote heart health, dietary changes are crucial, especially the change in the quality of fat. These changes can have a major impact in relatively short time and can lead to dramatic improvements in public health in the long run.”

A Meal High In Saturated Fat Increases Inflammation

SaturatedFatLorenzo'sGrill2

Photo of Lorenzo’s Pizza, on Christian Street in my hometown of Philadelphia. Cheesesteaks are almost synonymous with this city.

My previous post described a study that found eating a meal high in fat, especially saturated fat, increased inflammation in the airways, contributing to asthma.

This post describes a study that found eating a meal high in saturated fat increased systemic (whole body) inflammation.  Consistent, low-grade inflammation is thought to contribute to atherosclerosis, and so, to heart disease.

The Effect Of Two Iso-Caloric Meals Containing Equal Amounts Of Fats With A Different Fat Composition On The Inflammatory And Metabolic Markers In Apparently Healthy Volunteers, Journal of Inflammation (London), January 2013

“Fifty four apparently healthy normal weight volunteers were given two iso-caloric meals with similar amounts but different composition of fats: a meal high in monounsaturated fats (MUFA), and a meal high in saturated fat (SFA).

The main finding of the present study was the elevation of the hs-CRP* level within 2 hours and prolonged hypertriglyceridemia within 4 hours as a result of a high saturated fat meal in apparently healthy non obese participants.

*CRP is C-reactive protein, a marker for inflammation

Dietary fat is known to increase insulin resistance, or to “paralyze insulin” as Dr. McDougall says. Insulin resistance makes it difficult to clear blood of glucose (carb). And saturated fat increases resistance to insulin more than other fats. This study lends support to the idea that fat “paralyzes insulin” via an inflammatory process … saturated fat was shown to increase markers of inflammation, and:

“Mediators of inflammation have been clearly shown to be involved in the induction of an insulin resistant state.”

A transient, macronutrient-related, microinflammatory response could explain, at least in part, the appearance of a dynamic insulin-resistant state which could be responsible for a postprandial hypertriglyceridemic response.

Evident from the quotes above, not only did saturated fat increase inflammation, but also triglycerides:

“In this study, the average triglyceride levels in the fasting state were normal, increased as expected after both meals, but continued to increase only after the high SFA meal, more profoundly in men than in women.”

“Postprandial hypertriglyceridemia accelerates atherosclerotic damage by initiating inflammation and affecting the endothelium.”

Men fared worse:

“We showed that the hs-CRP levels were affected by the SFA meal differently in women and in men, with a higher increase in men than in women.”

These effects were for a single meal, but:

“Since most people eat every few hours, it is reasonable to assume that following repeated high SFA meals they have continuous high levels of triglycerides and low-grade inflammation, with a borderline effect for gender.”

This is yet another piece of evidence showing how saturated fat contributes to the development of diabetes and heart disease. I just don’t get how people continue to claim saturated fat’s role in chronic disease is a myth.

Calcium Supplements Found (Again) To Increase Risk For Heart Attack, Stroke

I’m reposting this from April 2011 because I know so many people, women especially, who insist on taking calcium supplements.
________
The leading cause of death for women in America is heart disease.1 It now looks like some of those heart attacks (and strokes) may have been provoked by the calcium supplements women were taking to protect their bones. (Heart disease is the leading cause of death in men too, but I don’t think men are pressured as much as women to take calcium. Men may also be refraining because of the spectacular association between calcium and prostate cancer.)

A revisit of data in the huge Women’s Health Initiative (WHI) study found that women who took calcium supplements increased their risk for heart attack and stroke:

Calcium Supplements With Or Without Vitamin D And Risk Of Cardiovascular Events: Reanalysis Of The Women’s Health Initiative Limited Access Dataset And Meta-Analysis, British Medical Journal, April 2011

The original WHI analysis showed no such risk. But that was because thousands of women who were already taking calcium before the study weren’t told to stop. If those calcium-takers ended up in the placebo group (which was supposed to receive no calcium), you might expect them to show similar heart attack risk as intervention groups (which did receive calcium). That’s exactly what they found.

This new analysis looked at women who weren’t taking calcium before the study. If those women were randomized to a group that received calcium, it did indeed increase their risk for heart attack and stroke.

The Amount Of Calcium Didn’t Matter

Here’s Dr. Ian Reid, senior author of the new analysis:

It is actually taking a supplement that matters, not how much of it you take, that causes this increase in heart risk.”

And from a HeartWire interview:

“That makes sense, [Reid] says, since even small levels of supplemental calcium create “abrupt” increases in blood calcium levels within hours. This speaks to one criticism levied at the group’s earlier work — namely, that the cardiovascular events seemed to be occurring too swiftly to be related to calcified plaques.

MI spikes likely reflect a more acute response to blood calcium levels, including changes in platelet function, blood coaguability, or endothelial cell activity.”

Calcium Supplements And Cardiovascular Events: New Data, More Debate, HeartWire, April 19, 2011

I would like to add to those mechanisms something readers of this blog already know – calcium lowers vitamin D levels, and vitamin D is thought to be cardio-protective:

“If serum levels of calcium are high, production of 1, 25 D is suppressed by reduced parathyroid hormone production.”

Dairy Products, Calcium, and Vitamin D and Risk of Prostate Cancer, Epidemiologic Reviews, 2001

The present analysis found no benefit in taking vitamin D.

Dr. Reid: “Our own recommendation is to critically review the use of calcium supplements, since the data in this paper suggests that they do more harm than good.”

Women Taking Calcium Supplements May Risk Heart Health, Researchers Say, HealthDay, April 19, 2011

1 CDC: Leading Causes of Death in Females, 2010