I doubt that a molecule as large as IGF-1 will survive the stomach or pass thru the intestine’s wall. If that’s the case, treating dwarfism caused by IGF-1 should be as easy as drinking milk. But I did read a story just recently that mother’s who drink a lot of milk have taller children, so you might google that and see if it relates to IGF-1.

Milk does have a lot of protein, and Dr. Longo recommended very low protein consumption in order to keep IGF-1 low, so in any case, drinking very much milk would be counter productive in the goal of lowering IGF-1.

Note that drinking soy milk has the same effect on circulating IGF-1 levels as drinking cows’ milk. Soy milk does not contain IGF-1 so the effect doesn’t come solely from IGF-1 in cows’ milk.

See the American Association for Cancer Research paper;

Effects of Tomato- and Soy-Rich Diets on the IGF-I Hormonal Network: A Crossover Study of Postmenopausal Women at High Risk for Breast Cancer. John M. McLaughlin1, Susan Olivo-Marston1, Mara Z. Vitolins, Marisa Bittoni, Katherine W. Reeves, Cecilia R. Degraffinreid1, Steven J. Schwartz1, Steven K. Clinton1, and Electra D. Paskett. Cancer Prev Res May 2011 4; 702 – http://cancerpreventionresearch.aacrjournals.org/content/4/5/702

IGF-1 is a polypeptide and the digestive tract contains powerful peptidase enzymes so whatever IGF-1 does make it through to the circulation it will be in very small quantities;

“the absorption of IGF-1 from the intestinal tract (which has been estimated by some authors to be absent and by other authors to be measurable but small) is considered to be an insignificant determinant of circulating IGF-1 levels.”

Report of the Royal College of Physicians and Surgeons of Canada – Expert Panel on Human safety of rbST. Dr. Stuart M. MacLeod, Dr. Réjeanne Gougeon, Dr. Gerald S. Marks, Dr. Michael Pollak, Dr. Milton Tenenbein, Ms. Cindy Woodland. http://www.hc-sc.gc.ca/dhp-mps/vet/issues-enjeux/rbst-stbr/rep_rcpsc-rap_crmcc_final-a-eng.php#igf

The American Cancer Society has looked at IGF-1 levels in milk from cows treated with synthetically produced growth hormone and has not found sufficient evidence to say one way or the other whether there is any risk to human health from the increased IGF-1 levels.

The synthetic growth hormone is not permitted in dairy production in the European Union.

See http://www.cancer.org/cancer/cancercauses/othercarcinogens/athome/recombinant-bovine-growth-hormone

Interestingly, some studoes have shown that milk consumption, which increases circulating IGF-1, can have a protective effect against certain cancers;

Milk Intake, Circulating Levels of Insulin-Like Growth Factor-I, and Risk of Colorectal Cancer in Men. Jing Ma, Edward Giovannucci, Michael Pollak, June M. Chan, J. Michael Gaziano, Walter Willett and Meir J. Stampfer. JNCI J Natl Cancer Inst (2001) 93 (17): 1330-1336. – http://jnci.oxfordjournals.org/content/93/17/1330.full

“Conclusion: Intake of dairy products was associated with a modest increase in circulating IGF-I levels, but intake of low-fat milk was associated with lower risk of colorectal cancer, particularly among individuals with high IGF-I/IGFBP-3. This subpopulation, which is at increased risk of colorectal cancer, might benefit the most from specific dietary intervention.”

At the moment I haven’t come across a convincing study showing that consumption of milk is bad because of the IGF-1 effects.

If you find one, please let me know.

Sarah

No, no interests in the dairy lobby but I am a scientist with a medical background and will always try to find relevant well-conducted studies for evidence 🙂

Sarah

Hi there. I joined this forum because of this thread.

Ladyboomer, I tend to avoid milk and milk products on fast days because they give a disproportionate insulin response, despite being high in protein.

http://www.direct-ms.org/pdf/EvolutionPaleolithic/Milk%20and%20insulin.pdf

I tend to have fish and salad. But then, we know too much protein is bad for us, so I limit this to about 7 oz.

Also, I agree with Sarah. Here’s another abstract to throw into the mix:

http://jama.jamanetwork.com/article.aspx?articleid=194858#qundefined

We need to be careful regarding articles on the internet because we don’t know if the author has some vested interest/beliefs which might alter their perception or slant, so they may well latch on to one aspect of the evidence to support that belief, ignoring any evidence to the contrary. This isn’t a fault as such, more a human characteristic. Science papers are peer reviewed(*), whilst articles on the internet are often not. Indeed, articles in magazines are edited for style and content more than veracity because it takes an expert to see if the expert author is being fair. So we need to beware of scare stories.

It would be a shame to cut out a relatively cheap, nutritious foodstuff which may have a protective effect against some conditions and is a good source of calcium, on the basis of some evidence which might not be complete, It might not be the milk per se which is to blame for the increase in IGF-1 levels, it might be the increase in protein, for example, or other factors.

That milk and milk products (except for hard cheese) gives a disproportionate insulin response and seems to increase IGF-1 levels makes me wonder if there is something about milk that induces an increase in hormones, but that’s just speculation.

I shall continue to drink milk.

(* “Peer Review”. When a scientific paper is submitted to a journal for publication it is sent out to other experts in that field to check that the science is sound and the conclusions are valid before the paper is published. This avoids egg-on-face incidents because a respect3e4d journal would not like to publish bad science. Even so, some papers are controversial and will induce a flurry of heated exchanges. This helps prevent extravagant claims and ill-thought-out advice being given out by the scientific community. It does not prevent the media from latching onto one tiny aspect, and wild headlines.)

Eileen,

Here’s my idea regarding protein. Protein is filling and makes it easier on fast days, so I’d recommend it when starting out. But, you’ll remember from the original show, Dr. Longo, from USC, I believe, was advocating very low protein consumption in order to lower IGF-1 (growth hormone) and reduce your chances of getting cancer. The level he was advocating, about 15 grams a day as I remember, would be very difficult to do. And it was Dr. Longo who had Michael do the 31/2 day fast which lowered his IGF-1 about 50% and later Michael discovered that 5:2 also lowered IGF-1 about 50%.

My thinking is that it’s lack of protein on fast days that lowers IGF-1. I suspect that the IGF-1 level is just a proxy for a whole series of changes the body makes in order to deal with lack of protein in the diet. Unlike energy, protein can’t be stored, so my thinking is that the body tells cells which are old, malfunctioning and generally not well, to die and thereby make their protein available for new synthesis. As Dr. Longo said, repair mode instead of go-go mode, where the body puts up with the dodgy cells because there’s plenty of protein available in the diet. Some of these dodgy cells could become cancer cells. If they do, they’ll no longer be subject to the body’s regulation so I want to get into this repair mode for sure, so now that I’m used to fasting, I just eat vegetables and finish with some fruit.

The general idea the the body mines muscle for protein doesn’t make any sense. The body will need the muscle as well as the brain to find food, so I’m sure it just changes regulation as Dr. Longo explains.

The amount of protein we should be taking in to replace that lost from turnover is 0.8g per kg bodyweight. But that’s dry weight, not the weight of the piece of meat etc, and includes the protein found in bread, beans, pulses etc.

That’s daily, so I disagree that it’s not important to restrict protein on non-fast days. Vegans had the lowest levels of IGF-1, even lower than Cronies, in a study by Longo.

The way I look at it is that 1g protein is approx. 4 kcals, so a piece of mainly protein meat or fish to equate for my needs (0.8 x ideal weight 72kg, say about 60g dry weight, which is the equivalent of 240kcals protein, which is about 7oz fish etc.

Which, with a yummy salad makes my fast day meal.

In a starvation situation where the glycogen has been all used up, the muscles are fair game for degradation because the body wants to protect the essential organs, so muscle loss is possible. But we are not starving, we are fasting.

I have seen photos of a vegan bodybuilder, so the need for lots of protein to protect the muscles is a bit of a myth. It’s the training that matters. Mind you, a body builder needs more calories because if the exercise, so might get more from vegan sources than the ordinary person.

But protein is satiating, which is why Mosley suggests a boiled egg for breakfast.

Great link. Good study indicating the need for protein restriction, rather than calorie restriction, to reduce IGF-1.

I didn’t mean to imply that daily protein restriction isn’t important, but I don’t really “count” protein on non-fast days for the same reason I don’t count calories, I’m too lazy. So I rely on two days a week of no protein. I haven’t seen any actual data from studies, even in mice, of intermittent protein restriction and IGF-1. However, the fact that intermittent calorie restriction, which necessarily results in protein restriction to a great extent, does sometimes at least lower IGF-1, is a good sign. In any event, not eating protein on fast days lowers overall protein consumption.

Milk is said to limit the absorption of beneficial compounds from tea, coffee and cocoa. So it’s not that great. Also it’s high on methionine, which seems to be probably the most important amino acid to reduce with regards to protein.

StraR: A link to the original paper is here: http://dx.doi.org/10.1016/j.cmet.2014.02.006.

In the study people eating the lowest levels of protein (<10% calories from protein) had a 4x reduction in their mortality from cancer compared to people in the highest protein eating group (>20% calories from protein). The low protein eaters also had a much reduced rate of mortality from diabetes.

Note: While protein from plant sources was found to be better, it’s not without any possible harm – which is not how the media are reporting the study. So vegans (myself included) shouldn’t feel too smug, and perhaps should reconsider eating quite so much tofu and legumes (chickpea curry included!).