T Nation

What I learned from PubMed

I’ve been scouring the PubMed database reading up on insulin sensitivity, fish oil, supplements and other nutritional info. It struck me that most of these studies are done on diabetics, obese, or elderly people. It finally occurred to me that that’s who needs the help - or more cynically, the meds.

What’s to gain in understanding people who are already healthy? And, you don’t have to do studies to sell supplements to healthy people, because you’re not claiming that you can make them better.

So, it leads me to question the validity of conventional wisdom about supplements, which now seem to be misappropriated from studies involving populations whose response does not match that of healthy adults. Specifically, most of the advise I’ve come to believe from this site would probably more accurately be prepended with “For diabetics…”

I guess this should be no surprise, that for healthy people, bodybuilders or not, supplements are really not necessary, if you have a healthy balanced diet- which consistently is reported as high fiber, low saturated fat, regardless of macro breakdowns.

All the magical properties of supplements only come into play if you are severely deficient in something to begin with, typically because of some disease or enzyme disorder.

That’s not to say there’s nothing to learn about nutrition for performance, but it seems pretty simple, and does align with the bodybuilding standard of sugar only around exercise, frequent fiber and protein meals, and a variety of fruits, vegetables, and lean proteins.

An interesting point, is that any non-bodybuilder considers high protein around 1g/kg, which would be considered criminally low around here, and except in the context of ketogenic diets, low carb seems to describe anywhere below 40% of calories, which again, on this site, would be considered a high carb bulking diet.

The most surprising detail, since I’ve read over and over from members and authors here that fish oil improves insulin sensitivity, is that consistently, in any study with healthy adults, it does not.

EDIT: I want to summarize.

  1. Common knowledge about nutritional supplements seems to be based on their effect on diabetics.
  2. You have to NEED supplements to gain their benefit.
  3. You are most likely not going to be limited in any way by a lack of supplements.

[quote]atypicaluser wrote:
The most surprising detail, since I’ve read over and over from members and authors here that fish oil improves insulin sensitivity, is that consistently, in any study with healthy adults, it does not.
[/quote]
Well, yeah. If your insulin sensitivity is already at peak, you’re not going to make it even better.

OTOH, even the bodybuilders aren’t necessary at peak sensitivity. Look at CT’s article not long ago where he discusses having felt he had too much body fat on his back, which is generally related to insulin resistance, even if minor relative to a type 2 diabetic.

Fish oil also has other benefits, including anti-inflammatory properties, so in the fish oil case there are still reasons to take it.

yorik - yes, I agree there are lots of good reasons to take fish oil, but one I expected to find, and consistently didn’t, was an improvement in insulin sensitivity. I don’t think a person’s insulin response is either “Good/Peak” or “Bad,” there’s a range, based on a number of factors. What I found though was that fish oil is not one of those factors.

As Biotest, and the authors at T have mentioned before, they’re called supplements for a reason.

In all supp. advertisements regardless of manufacturer or intended use, be very wary of the word MAY, as in-

May improve…

or

has been shown to…

and

provides essential substrate for the production of…

Because even someone with a mediocre grasp of the english language and a snatch hair of physiology can put those together to become-

"Eating a stick of butter May Improve testosterone levels because the cholesterol in Bettys Butter provides essential substrate for the production of testosterone!

Increased testosterone has been shown to improve mood, increase math skills…
So buy Betty Botters Butter!"

And there isn’t a statement in there that can technicaly be considered misleading or false.

^

exactly

the most common phrase in marketing a health product (or even a pharmaceutical product) is “may help to reduce X” because it gets them off the hook if the product is nothing but a worthless placebo for you

I’ve been saying the same thing forever about fish oil. While I do use fish oil, I dont use it for improving my insulin sensitivity. It has a nice anti-inflammatory effect (which is why I use it) regardless of age.

But, to be fair, consuming the fish oil at an early age can certainly help with the insulin insensitivity that occurs during ones aging process.

[quote]cyph31 wrote:
^
exactly

the most common phrase in marketing a health product (or even a pharmaceutical product) is “may help to reduce X” because it gets them off the hook if the product is nothing but a worthless placebo for you[/quote]

If it does work as a placebo, it’s not worthless.

Fish oil increases fat loss through a bunch of different mechanisms, including altering genetic expression.

[quote]Aleksandr wrote:
Fish oil increases fat loss through a bunch of different mechanisms, including altering genetic expression.[/quote]

Exactly, fish oils effects do extend beyond just insulin sensitivity.

Oh, btw, I think it’s awesome that you are doing lit searches in order to assess the effectiveness of things, but be careful. I don’t know what you do for a living, and how much background you have with statistics, but whether something is “effective” and whether it is statistically significant aren’t always the same.

Missing a moderating or suppressor variable will do the trick, for instance. The design can also be inadequate. For example, take the following design:

Two groups, with participants randomly assigned. One group gets fish oil, the other gets some neutral placebo (water pills, maybe). Yuo conclude that the fish oil had no effect on insulin sensitivity, p > .05. Pretty straight forward, right?

Consider that in both groups, there will be people of varying levels of insulin sensitivity. The ones with optimal insulin sensitivity in the experimental (fish oil group) will not experience any improvement.

Even if it is effective for everyone else, the individuals for whom it is not effective could result in overlapping ranges (by range, I mean [M +/- SEM]), and thus the treatment would not result in statistical significant.

Aleksandr - yes, agreed, that is a good alternate perspective on the point that you have to qualify any result with what condition you have to be in to get that result, or in this case lack of result.

Making the blanket statement that supp X increases quality Y is completely misleading if you leave out that it only does that if you have diabetes for example, and is entirely the reason for the vague wording on the bottle, as mentioned.

One more thing - if it works as a placebo, it’s not worthless, but that doesn’t mean it’s worth what you paid!

It is only a study of one, but since i started taking 2 spoonfuls of cod liver oil a day, i have gotten noticeably leaner, at an age when metabolism is supposed to be slowing down (30), im not even trying to diet or anything and am the leanest i have been since i wrestled at a very low weight(135) in highschool. i am now 185, my heaviest is 205. I still play BJJ, so i get some hard cardio, but ive done that and not been tis lean. and i reduced lifting with weights to one day a week since ive been in the mood to do more grappling (though i do pull ups/body weight squats and similar things if i get bored)

the only other thing is a use like 4 tablespoons of olive oil in the fruit veggie protein powder smoothies i make

so i think these oils help with fat loss