February 1, 2023

SEASON 2, EPISODE 43 (clip 3)

I want to ask you another question around sort of the importance of the pulsatile and first insulin responses in the story of type 2 diabetes sure did you unpack that a little bit for listeners yes so so insulin secretion is is quite hard to explain because it could mean anything i mean basically you’re saying the insulin that’s released postprandially but what’s

Really important seemingly for normal physiology is something we call the first phase insulin secretion it can basically be defined as the amount of insulin that is secreted in the first 10 minutes following a rise in blood glucose so basically normally let’s say when you eat your pancreas if it’s healthy is very efficient at detecting any change in blood glucose

Concentration so the moment your pancreas is able to detect that your blood glucose has gone up even 0.3 millimoles per liter you get this really powerful insulin spike and it’s where your insulin goes up really fast really high um in the first 10 minutes and that’s called the first phase insulin response um so often people use insulin spike in a negative sense

Like oh you shouldn’t eat carbs because it will cause an insulin spike and this is a really this is a misunderstanding of physiology because having an insulin spike that goes up and then comes down very quickly is a very effective way of managing postprandial glucose concentrations because the moment your insulin goes up it shuts down hepatic glucose output so your

Liver no longer releases glucose which it does in the fasting state it also causes glucose to be taken up into the muscles very quickly and very efficiently it stops lipolysis so if you’re healthy and insulin sensitive having a marked insulin peak is very important for controlling postprandial glucose and postprandial fat metabolism what happens early on in type

2 we see this in pre-diabetes the first phase insulin response is basically halved so yes you get a response but it’s not this peak that you’d see in healthy people and by late stage type 2 this differs between people but it might be 10 years after diagnosis there’s barely a blip so if you try to measure the first phase insulin response you can barely see a blip

And let me just reiterate the way we measure this is very difficult to measure which is why we previously haven’t known so much about it is that you can really only get a picture of how well the beta cells are working by either using an intravenous glucose tolerance test so this is like an oral glucose tolerance test but you inject the glucose into a vein or a

Hyperglycemic clamp and this i mean on average they can be three whole three four hundred pounds um in the uk per clamp um all in um so they’re very difficult to do they’re quite time consuming um and they’re expensive but they do tell us important things about beta cell function so that’s first phase insulin and i think you mentioned pulsatile insulin release so

This actually is even less studied than the first phase insulin response um and so pulsatile insulin secretion basically refers to how insulin in the healthy physiological state is released in a pulsatile fashion um so it looks like the pulses might be five to seven minutes apart and basically it’s just insulin going up and going down and going up and going down

Um and this is quite normal in endocrinology so a lot of the hypothalamic hormones do have a similar pulsatile insulin secretion um but its importance is very clear in or we know that from studies where um researchers have infused insulin into a vein in a pulsatile fashion and then they’ve infused insulin into a vein the same concentration of insulin but flat

So removing the peaks and troughs and what those data showed is that if you infuse insulin flat you basically cause insulin resistance certainly in the liver interesting yeah absolutely um whereas if you you infuse the same concentration in the pulsatile fashion it reduces the insulin resistance um the the physiology behind how it’s pretty incredible how the

Pancreas itself secretes insulin in this pulsatile fashion isn’t fully understood but you can even see an isolated islet cells so if you take out the islets and you look at them in vitro you know kind of on the bench you can see this almost intrinsic pulsatile secretion um so it’s pretty fascinating yeah don’t know too much about how it goes wrong but certainly

That seems to be a defect early in type 2 and in fact you can detect a loss of pulsatile insulin secretion in normal glycemic relatives of people with type 2 diabetes so someone who’s got totally normal glucose but just has a mum or dad with type 2 you already see this loss in the pulsatile insulin secretion that’s fascinating yeah and and nicola where’s the

Potential application here with technology the use of continuous glucose monitoring systems especially as a proxy for insulin output what are your thoughts on that and where yeah this is tough i mean i love cgm cgms have really changed certainly the way i manage a lot of my patients um but unfortunately insulin is so important whether it’s insulin or c-peptide so

C-peptide is basically it’s released at the same time of it as insulin but it’s not taken up by the tissues in the same way so c-peptide can be a useful marker for insulin secretion unfortunately there are no ways yet of measuring insulin and c-peptide um easily and outside of a lab that will change the game if someone can figure out a way to measure insulin or

C-peptide the way we measure glucose that will change the landscape um i mean i i really genuinely hope there are teams working on this um because it’s such an important question um so in in terms of the certainly cgm i like cgms because i think they demonstrate the effect of foods on on blood glucose levels i think it empowers patients to see that and i think it

Helps them manage their either pre-diabetes or type 2 diabetes that way but i would like to patients to be able to do that with insulin too but maybe i think that’s probably 10 years away yeah that would be definitely an incredible breakthrough and as you mentioned i think cgms are a terrific learning tool for patients just to for them to really put their finger

On what’s happening in in the blood in reaction to different foods and i think for a lot of folks it’s a pretty big eye opener to see some of these responses to things that they you know maybe it may have taken for granted or hadn’t realized and so definitely um a very useful tool but if we come back to this idea of food environment which is obviously massively

Important um you mentioned the weight loss success of folks is not very good you know regain within five years almost across the board all of these protocols when we start to see this ability to get into caloric deficit to help with weight loss we know we can do it we just can’t help clients and patients maintain it um so are we just you know is it doom and gloom

Here are we stuck with this food environment how can we start to shift uh things to help folks out sure i mean so much so let me just reiterate in terms of losing weight and weight regain i mean yes the food environment is huge and we’ll just come to that in just a sec but it is important to illustrate we now know a lot about physiology in particular appetite

Hormones and there’s clear data that when you lose weight all of the hormones that make you want to eat increase for sure and those effects seem to be maintained certainly up to a year after you lose weight so i think it’s important to let people know when they feel hungry and when they’re just craving for food after they lose weight that is a kind of a normal

Physiological response and that’s one of the reasons why it makes sustained weight loss maintenance so challenging um but certainly certainly the food environment is huge and like when i talk to my colleagues about i mean i think the diabetes prevention program we have here is terrific but you know imagine if you just attended an hour-long session you’re really

Excited you’ve lost some weight um and you walk down the high street after the session and there are seven or eight different places where food smells are wafting out um advertising lots of cheap palatable food for you know one pound fifty you can eat your dinner you don’t need to prepare it you know human beings are human beings we work long hours we’re tired

We don’t have much time stress levels are high stress levels are high short and we’re easily tempted um and in that kind of situation all of the education in the world unfortunately isn’t going to change our um our natural human responses to the environment around us um but i i do have some optimism and we’ve we’ve seen the sugar attacks um i mean that was kind

Of a no-brainer in the sense that no one needs sugar it doesn’t have any nutrients um it’s pretty terrible for kids especially when it’s in liquid drinks you know some kids in the states are having 25 of their calories from coke sharking isn’t it absolutely yes so like i’m really pleased to see that um and i think there is a growing public understanding that in

Some ways we’ve been duped by food manufacturers um you know advertising foods is healthy um and and quite cynically using health claims to market their products i think there’s growing understanding that we have to be as consumers more cynical about our foodscape um but the real thing is is going to be further um political changes i mean so so darius um safari

In a tufts has some terrific ideas on this um i mean quite clearly to change food intake um you need point of sale either taxation or incentives so for example where researchers have lowered the prices of fruit and vegetables in a canteen you can immediately see people start consuming more of those products if they then increase the price of fruit and vegetables

People consume fruit fewer of those products so certainly pricing is going to influence food intake um and what i would like to see in it it’s a political question and it’s that’s not my role but i i think this was the kind of thing that would work is that when you go to a food outlet stuff like chips or fries are let’s say three dollars or four dollars whereas the

Vegetables or the oily fish is heavily subsidized now i’m not experienced in this area at all but like i say professor mozafarian i think has some very realistic ideas um some very implementable ideas and it’s going to be a case of changing unfortunately the law and this is going to take a lot of public pressure too um the public have to be in on this um obviously

The politicians um is we certainly have this in the uk um they work with and i think they in certain certain circumstances they should they should work with food industry but food industry is certainly way too powerful they have we’ve seen with the sugar tax how much the beverage industry is fighting the sugar tax because guess what they know that it’s going to

Reduce their their sales and so the politicians frankly we’re not going to get policy changes or legislative changes unless there is public pressure behind um these decisions um but but certainly changing the foodscape by sensible taxation um would be a useful strategy in my opinion

Transcribed from video
Is an 'Insulin Spike' a Bad Thing? (What Every Client Should Know) w Dr. Nicola Guess, PhD By Performance Nutrition Podcast