Saturated, Polyunsaturated, Monounsaturated Fats, Carbohydrate & Glucose-Insulin Homeostasis

(Michael - When reality fails to meet expectations, the problem is not reality.) #1

Discussion

The results of this systematic review and meta-analysis of randomised controlled feeding trials provide, to our knowledge, the most robust available evidence for the effects of dietary fats and carbohydrate on diverse glucose-insulin metrics. We identified divergent relationships of specific dietary fats with different measures of glucose-insulin homeostasis. For example, only energy intake substitution with PUFA was linked to lower fasting glucose, lower HbA1c, improve HOMA-IR, and improve insulin secretion capacity. These effects were generally seen whether PUFA replaced carbohydrate or SFA; interestingly, insulin secretion capacity also improved when PUFA replaced MUFA. In comparison, MUFA consumption did not appear to significantly influence fasting glucose, compared to others macronutrients; but was seen to reduce HbA1c and improve HOMA-IR in comparison to either carbohydrate or SFA. Exchange of SFA for carbohydrate had little observed effects on most measures, except for reduced fasting insulin and a borderline significant effect on C-peptide.
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Throwing this out here for anyone who understands what these folks are talking about. Please explain in layman’s terms. Thanks.

(Michael - When reality fails to meet expectations, the problem is not reality.) #2

@ctviggen

If you get a chance and some time, I’d appreciate your response to this study. Thanks.

(bulkbiker) #3

Mozzafarian is very pro seed oil… anything with his authorship will show that bias.

I’ll have a read but I’m always wary of meta analyses as the quality of the underlying studies are rarely subjected to very close scrutiny… As almost all fats in food contain all three SFA, PUFA and MUFA in differing proportions they can only show that some variance in composition may have an effect. Which immediately raises my warning flags when they talk about PUFA alone doing stuff.

(bulkbiker) #4

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0.04 mmol/l a “decrease” in fasting glucose… is probably not even measurable by any meter available to anybody… ever…

(Bunny) #5

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They are talking about room temperature of fats meaning the less solid it becomes at room temperature the better it is for you.

The hydrogenated trans fats or fully hydrogenated saturated trans fats are the only ones I would be concerned about.

If your eating lots and lots of fat I would not even worry about it and getting B-6 from more nutrient dense foods or supplementing with B-complex Vitamins.

B-6 is the star of the show in this story:

From Another Source: “…These data indicate that short-term vitamin B-6 restriction decreases plasma (n-3) and (n-6) PUFA concentrations and tends to increase the plasma (n-6):(n-3) PUFA ratio. Such changes in blood lipids may be associated with the elevated risk of cardiovascular disease in vitamin B-6 insufficiency. Topic: fatty acids. …” …More

References:

[1] “…Monounsaturated fats have a single carbon-to-carbon double bond and the most representative of these fatty acids is oleic acid, contained in olive oil. The result is that it has two fewer hydrogen atoms than a saturated fat and a bend at the double bond. …” …More

[2] “…Vitamin B6 is part of the vitamin B group of essential nutrients. Its active form, pyridoxal 5′-phosphate, serves as a coenzyme in some 100 enzyme reactions in amino acid, glucose, and lipid metabolism. …” …More

[3] “…If dietary saturated fat intake has little to do with saturated levels in our blood, then what does? There is, in fact, sound evidence that dietary carbohydrate is a major determinant of serum saturated fat levels. We know this because two respected research groups [16,17] fed humans carefully measured, weight-maintaining diets either high in carbohydrate or moderate in carbohydrate. In both studies, blood levels of saturated fats went up dramatically on the high carb diets, even though they were very low in fat. On its surface, this looks like a paradox; but with a little thought it makes sense. A high carbohydrate intake has two effects in the body that promote higher levels of saturated fat. First, carbohydrates stimulate the body to make more insulin, which inhibits the oxidation of saturated fat. Thus, when insulin levels are high, saturated fat tends to be stored rather than burned as fuel. Second, a high carbohydrate intake promotes the synthesis of saturated fat in the liver. …” …More

(Bob M) #6

Replacing carbohydrate with PUFA significantly lowered HbA1c (-0.11%; -0.17, -0.05) and fasting insulin (-1.6 pmol/L; -2.8, -0.4). Replacing SFA with PUFA significantly lowered glucose, HbA1c, C-peptide, and HOMA.

Here’s my theory. The PUFA causes your fat cells to be insulin sensitive, meaning they suck up more insulin and blood sugar. This should lead to a (relative) decrease in both blood sugar and fasting insulin, thereby leading to a decrease in HbA1c and HOMA-IR.

Homa-Ir is calculated as follows:

HOMA-IR was calculated according to the formula: fasting insulin (microU/L) x fasting glucose (nmol/L)/22.5.

So, if both these go down, you’ll get a better HOMA-IR.

But you’ll be getting fatter.

Note: This is why looking at certain markers without context isn’t a good thing to do.

The answers might be found here (posted on Twitter by Tucker Goodrich, who believes PUFAs are the source of all evil), but I haven’t had time to analyze:

In this, they used a “hyperinsulinemic euglycemic clamp”, which is supposedly “da bomb” when it comes to determining fat cell insulin resistance/sensitivity. I have not had time [edit - to review].

More edit: As to the latter, we watch TV using a computer. I tried to go from windows 7 to windows 10…and it wouldn’t boot. So, I bought parts for a computer to build a new one (already had a case, power supply, video card), installed software, etc. Spent the whole weekend just getting us to be able to watch the Super Bowl. We have a device that serves us cable TV over our hardwired network, and I store this TV on our 10TB server.

Have I mentioned that I’m an engineer? :grinning:

So, I’m a bit behind in pretty much everything.