Another paper from the controversial PURE study.

[pjoshea13]

New study below.

"Reducing saturated fatty acid intake and replacing it with carbohydrate has an adverse effect on blood lipids. Substituting saturated fatty acids with unsaturated fats might improve some risk markers, but might worsen others."

Because of my PCa research, my primary concern is with triglycerides.

"Intake of total fat and each type of fat was associated with ... lower triglycerides, ... {& lower} ratio of triglycerides to HDL cholesterol". The latter is a surrogate for insulin resistance - lower is better.

"Higher carbohydrate intake was associated with ... higher triglycerides, {& higher} ratio of triglycerides to HDL cholesterol"

"Replacement of saturated fatty acids with carbohydrates was associated with the most adverse effects on lipids, whereas replacement of saturated fatty acids with unsaturated fats ... seemed to worsen others (HDL cholesterol and triglycerides)."

i.e. lower HDL-C & higher triglycerides, making for a worse ratio of triglycerides to HDL cholesterol (more insulin resistance).

-Patrick

thelancet.com/journals/land...

"Association of dietary nutrients with blood lipids and blood pressure in 18 countries: a cross-sectional analysis from the PURE study." (29 August 2017)

"Background

The relation between dietary nutrients and cardiovascular disease risk markers in many regions worldwide is unknown. In this study, we investigated the effect of dietary nutrients on blood lipids and blood pressure, two of the most important risk factors for cardiovascular disease, in low-income, middle-income, and high-income countries.

Methods

We studied 125 287 participants from 18 countries in North America, South America, Europe, Africa, and Asia in the Prospective Urban Rural Epidemiology (PURE) study. Habitual food intake was measured with validated food frequency questionnaires. We assessed the associations between nutrients (total fats, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, carbohydrates, protein, and dietary cholesterol) and cardiovascular disease risk markers using multilevel modelling. The effect of isocaloric replacement of saturated fatty acids with other fats and carbohydrates was determined overall and by levels of intakes by use of nutrient density models. We did simulation modelling in which we assumed that the effects of saturated fatty acids on cardiovascular disease events was solely related to their association through an individual risk marker, and then compared these simulated risk marker-based estimates with directly observed associations of saturated fatty acids with cardiovascular disease events.

Findings

Participants were enrolled into the study from Jan 1, 2003, to March 31, 2013. Intake of total fat and each type of fat was associated with higher concentrations of total cholesterol and LDL cholesterol, but also with higher HDL cholesterol and apolipoprotein A1 (ApoA1), and lower triglycerides, ratio of total cholesterol to HDL cholesterol, ratio of triglycerides to HDL cholesterol, and ratio of apolipoprotein B (ApoB) to ApoA1 (all ptrend<0·0001). Higher carbohydrate intake was associated with lower total cholesterol, LDL cholesterol, and ApoB, but also with lower HDL cholesterol and ApoA1, and higher triglycerides, ratio of total cholesterol to HDL cholesterol, ratio of triglycerides to HDL cholesterol, and ApoB-to-ApoA1 ratio (all ptrend<0·0001, apart from ApoB [ptrend=0·0014]). Higher intakes of total fat, saturated fatty acids, and carbohydrates were associated with higher blood pressure, whereas higher protein intake was associated with lower blood pressure. Replacement of saturated fatty acids with carbohydrates was associated with the most adverse effects on lipids, whereas replacement of saturated fatty acids with unsaturated fats improved some risk markers (LDL cholesterol and blood pressure), but seemed to worsen others (HDL cholesterol and triglycerides). The observed associations between saturated fatty acids and cardiovascular disease events were approximated by the simulated associations mediated through the effects on the ApoB-to-ApoA1 ratio, but not with other lipid markers including LDL cholesterol.

Interpretation

Our data are at odds with current recommendations to reduce total fat and saturated fats. Reducing saturated fatty acid intake and replacing it with carbohydrate has an adverse effect on blood lipids. Substituting saturated fatty acids with unsaturated fats might improve some risk markers, but might worsen others. Simulations suggest that ApoB-to-ApoA1 ratio probably provides the best overall indication of the effect of saturated fatty acids on cardiovascular disease risk among the markers tested. Focusing on a single lipid marker such as LDL cholesterol alone does not capture the net clinical effects of nutrients on cardiovascular risk."

[periclesBC]

Gosh, it seems we've seen quite a few studies link saturated fat with Pc. Would be nice to get back to enjoying some of those long abandoned saturated fat goodies, like drumsticks and chicken livers!

[pjoshea13 in reply to periclesBC]

There are U.S. studies that reported associations for saturated fat & PCa, but I'll first mention a very large European study [1] that didn't. Not because I like to cherry-pick, but because it raises questions about the meaning of such studies & the difficulty of reconciling glaring differences.

"This was a multicenter prospective study of 142,520 men in the European Prospective Investigation into Cancer and Nutrition (EPIC)."

"After a median follow-up time of 8.7 y, prostate cancer was diagnosed in 2,727 men."

"There was no significant association between dietary fat (total, saturated, monounsaturated, and polyunsaturated fat and the ratio of polyunsaturated to saturated fat) and risk of prostate cancer. The hazard ratio for prostate cancer for the highest versus the lowest quintile of total fat intake was 0.96".

Total fat as a percentage of energy, ranged from 31.3% (1st quintile) to 40.4% (5th). Saturated fat ranged from 10.1% to 17.2%. [2]

The U.S. NIH-AARP diet and health study, which had "288,268 men with average follow-up of nine years, 23,281 prostate cancer cases", reported that:

"Total fat and mono- and polyunsaturated fat intakes were not associated with incidence of prostate cancer."

In this instance, total fat as a percentage of energy, ranged from 20.3% to 40%. Saturated fat from 5.8% to 13.3%.

The risk factors by quintile for saturated fat for ~19,000 nonadvanced cases:

1.00 1.01 0.99 1.02 1.01

For the ~3,000 advanced cases, the saturated fat multivariable risk factor for the 5th quintile was 1.21, compared the the first (1.00). But the number of cases in Q5 was only 570, compared to 582 in Q1. Makes me wary.

It is common for men with PCa to alter their diets. The Physicians’ Health Study [4] used "926 men with non-metastatic prostate cancer ... who completed a food frequency questionnaire a median of five years after diagnosis and were followed a median of 10 years after the questionnaire."

This was a mortality study, but there were only 56 PCa deaths.

"Saturated fat as a percentage of energy, ranged from 6.6% to 12.7%.

Deaths by quartile: 12 7 16 21. (not well-behaved)

PCa mortality risk factors by quartile: 1.0 0.54 1.12 1.71.

However, this was their bottom line:

"Men who obtained 5% more of their daily calories from saturated fat and 5% less of their daily calories from carbohydrate after diagnosis had a ... 2.8-fold increase risk of prostate cancer-specific mortality"

I'd be happier if they were not dealing with such low numbers.

-Patrick

[1] ajcn.nutrition.org/content/...

[2] ajcn.nutrition.org/content/...

[3] ncbi.nlm.nih.gov/pmc/articl...

[4] ncbi.nlm.nih.gov/pmc/articl...

[Hidden]

Cherry picking at it's finest.

[Sisira]

I am guided by my Lipid Profile blood test which indicates the serum levels of TC, LDL, HDL, Triglycerides and the ratio of TC to HDL. Over the years I have learned about saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, carbohydrates and how they can affect the cholesterol and triglyceride levels with our daily food and nutrition. Most of my learning has come from qualified physicians including some good cardiologists and reading some good articles written by them. My entire lipid profile has so far remained to be almost perfect and also with no BP or cardio vascular issues.However my wife had problems in her lipid profile and also she had high BP. By following the advice given by a cardiologist, within 2 years she also manged to reach the same status like me which is being continued. Simply both of us went on the basis saturated fats, animal fats, trans fat, dairy products, egg yolks and hi-glycemic carbohydrates are bad when there is a tendency for lipid and cardio vascular issues and also for diabetic people. Regular exercise is a must and how to change our diet has individual other concerns too. We have no PROBLEM. That is what we want.

I have never heard of ApoB and ApoA and I don't think they will ever appear in our Lipid Profile blood test in this decade or so. This type of research papers and their findings should be read by our qualified physicians and if appropriate they should advise us what to do. I just don't want to wear a NEW HAT causing confusion in my head and disturbing the equilibrium I already have in my metabolic functions.

Thanks

Sisira

[38carbon]

Thanks for the clarity Sisira