Sure. Here you go. Let's do it in steps so it makes sense. It would also be something you could show your husband which he could explore for himself, without you having to explain it. This is everything from above but organized and put in order.
First, read these 2 newsletter from Dr McDougall as he discusses the issue of IGF-1, what it is, the concerns with it, etc
In this one, read the section on, "Growth Hormone Promotes Aging" till the end,
https://www.drmcdougall.com/misc/2006nl ... /aging.htmIn this one, read the section on, "Calcium Loss and Cancer Growth from Protein Concentrates"
https://www.drmcdougall.com/misc/2005nl ... 0pusoy.htmSome of the discussion may seem familiar as he went over it in his recent talk on Dairy (in the program) and also on Aging which I think was just posted.
Second, here is a study that I mention above which came out around the same time and basically supports everything Dr McDougall said in the above 2 links and his current updated talks..
Luigi Fontana, Edward P. Weiss, Dennis T. Villareal, Samuel Klein, John O. Holloszy. "Long-term effects of calorie or protein restriction onserum IGF-1 and IGFBP-3 concentration in humans." *Aging Cell. *(2008) Doi: 10.1111/j.1474-9726.2008.00417.x
Full Text
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673798/ABSTRACT
Reduced function mutations in the insulin/IGF-I signaling pathway increase maximal lifespan and health span in many species. Calorie restriction (CR) decreases serum IGF-1 concentration by ~40%, protects against cancer and slows aging in rodents. However, the long-term effects of CR with adequate nutrition on circulating IGF-1 levels in humans are unknown. Here we report data from two long-term CR studies (1 and 6 years) showing that severe CR without malnutrition did not change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast, total and free IGF-1 concentrations were significantly lower in moderately protein-restricted individuals. Reducing protein intake from an average of 1.67 g kg−1 of body weight per day to 0.95 g kg−1 of body weight per day for 3 weeks in six volunteers practicing CR resulted in a reduction in serum IGF-1 from 194 ng mL−1 to 152 ng mL−1. These findings demonstrate that, unlike in rodents, long-term severe CR does not reduce serum IGF-1 concentration and IGF-1 : IGFBP-3 ratio in humans.
In addition, our data provide evidence that protein intake is a key determinant of circulating IGF-1 levels in humans, and suggest that reduced protein intake may become an important component of anticancer and anti-aging dietary interventions.As a result of the study (and his other work) we invited Dr Fontana to the next Advanced Study Weekends.
In addition, here are some additional comments
that are not in the study but come from one of the subjects in the study who was in the CR Group. These comments were posted in the CR yahoo group of which I am a longterm member. They also confirm the above concerns and comments on protein and IGF-1.
"One of the most telling comparisons in the study was between our high-protein CR group and a cohort of ad-lib vegans. The CR Society group ate an average of 1772 calorie per day while the vegans ate 1980 calories per day. However, The CR group ate an average of 23.5% of total calories in protein while the vegans ate 9.6 percent protein. The excess protein eaten by our group was enough to completely nullify CR's IGF-I lowering effect."Lastly, here is a further conversation with this person,
which is not in the study but was posted on the CR group. He is discussing his own experiments with a few others in the CR Group which further reflect the same concerns about isolated/concentrated proteins. In addition, the concerns of of higher bioavailable proteins (more digestible and absorbable), plant or animal.
Question: How often do you and (...) test for IGF-1, monthly?
"We have tested IGF-1 about every 3 months since 2003. We test it along with the IGF binding proteins 1, 2 and 3, insulin, T3 and the VAP test.
We wanted to see how total protein fared against the above battery of tests as well as individual protein concentrates including whey, brewers yeast, soy protein isolate, nonfat yogurt, kefir. and a mixture of individual amino acids. The results were frightening -- each one of these substances sent IGF-1 significantly higher -- independent of total calorie intake.
The goal was to customize our CR diet to produce IGF-1 in the lower third of the reference range and to get IGFBP1, which is an indicator of SIRT1 activity, glucagon activity, etc., at the high end of the reference range.
This is consistent with the downregulation of energy availability and of anabolic activity that is shown in long-lived CR animals.
I have found, however, that protein absorbability makes a greater difference in IGF-I (and the binding proteins) than total protein, if the protein is from vegetables and grains, beans (this does not mean concentrates), and fruits."Hopefully, that will all make sense now. If not, let me know
In Health
Jeff