Associations of protein and fiber with Amyloid-β

[JimBG]

Does he offer any explanation for the increased protein for those over 65?

Longo's citation for his position on a different level of protein consumption with the dividing line at 65 is an epidemiological study of six thousand Americans he was involved with. The footnote is: M. Levine et al. and VD Longo, "Low Protien Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population," Cell metabolism (March 4, 2014), 19(3): 407-17. http://www.cell.com/cell-metabolism/ful ... 14)00062-X

[JimBG]

The study summary:

Mice and humans with growth hormone receptor/IGF-1 deficiencies display major reductions in age-related diseases. Because protein restriction reduces GHR-IGF-1 activity, we examined links between protein intake and mortality. Respondents aged 50–65 reporting high protein intake had a 75% increase in overall mortality and a 4-fold increase in cancer death risk during the following 18 years. These associations were either abolished or attenuated if the proteins were plant derived. Conversely, high protein intake was associated with reduced cancer and overall mortality in respondents over 65, but a 5-fold increase in diabetes mortality across all ages. Mouse studies confirmed the effect of high protein intake and GHR-IGF-1 signaling on the incidence and progression of breast and melanoma tumors, but also the detrimental effects of a low protein diet in the very old. These results suggest that low protein intake during middle age followed by moderate to high protein consumption in old adults may optimize healthspan and longevity.

[Orangeblossom]

Interesting, Jim.

'These results suggest that low protein intake during middle age followed by moderate to high protein consumption in old adults may optimize healthspan and longevity.'

well that would certainly give something to think of in our own diets.

I wonder if in the older people does the IGF- signalling naturally decline with age and therefore not such an issue and at that stage higher protein is generally more healthful due to helping with e.g. nutrients and preventing muscle loss. I'm just speculating here but wondering if that might tie in with this.

On the subject of IGF-1 I was just reading this on bones and osteoporosis. Might also be something to think of as well.

"IGF-1 in osteoporosis and vertebral aging

https://www.omicsonline.org/open-access ... ?aid=85633

Aging is accompanied by a decrease in bone structure and function, which significantly increases the risk of osteoporosis and fracture in elderly patients. Changes related with aging in bone health are the result of bone formation changing to bone resorption [58]. Some hormones, including IGF-1 and steroid hormones, are important for bone health and osteoblast activity. Knockdown of IGF-1R in osteoblasts leads to a reduction in adult bone size and adult bone mineral density [59,60]. Similarly, specific deletion of the IGF-1 product in the liver leads to a decrease in adult femoral length and bone mineral density [61,62]. In addition, a large number of clinical trials have shown that lowering the IGF-1 levels in circulation increases the risk of osteoporosis [63,64]. The studies clearly stressed the importance of IGF-1 in normal bone development, but the effect on vertebral structure and function of changes related with age induced by reduction of circulating IGF-1 remains unclear.

Interestingly, high levels of IGF do not always mean to increase bone health. Such as the early knockout of acid labile subunit (ALS) in circulation which is an important stabilizing protein of IGF-1 could reduce 60%~75% of IGF-1, but decrease cortical thickness in aged male rats [65]. This showed early or long-term IGF-1 deficiency promoted aging of long bones. In contrast, a recent study found that a decrease of IGF-1 in circulation in the adult resulted in a decrease in the cortical and cancellous bone thickness in the aging process [66]. Therefore, the different results indicate that IGF-1 deletions may depend on the different stage of life. Interestingly, in female rats, absence of IGF-1 lead vertebrae volume fraction to increase 67%, and the corresponding increase in density. Those suggest that IGF-1 regulates the aging depending on sex and time specific [67].

Certainly seems a complex issue. It's important to think of our overall health as well isn't it.

I quite like De Longo's ideas of having these low protein few days now and again. Think that might be more manageable for me, anyway. Might reap the benefits while avoiding the bad things. Not going to use the expensive Pro Lon supplement though, just things like homemade veggie soup and konjac noodles.

[Julie G]

Thanks JimBG and Orange for your references and musings. I'm fascinated by this one... especially the WHY?

[Orangeblossom]

Thanks JimBG and Orange for your references and musings. I'm fascinated by this one... especially the WHY?

Could it be about the neurotransmitters on the brain?

https://memory.foundation/2012/02/14/wh ... s-protein/

Proteins in our diet affect brain performance because they provide the amino acids (simply put, protein is made of amino acids) that make up our neurotransmitters. Think of neurotransmitters as biochemical messengers whose job it is to carry signals from one brain cell to another. These brain cells then transmit various signals to the different parts of the body to carry out their individual tasks. The better these messengers are fed, the more efficiently they deliver the goods. (Think Mother telling daughter to clean her room, and daughter then paying younger brother to do it – the more he’s paid, the cleaner the room!). You can see why it’s so important to be eating plenty of good protein – without it, the messengers won’t be working fast enough to keep your mind and memory sharp!
Protein – amino acids – are also essential for our happiness. When we don’t eat enough good protein, the brain can’t produce enough neurotransmitters such as serotonin, which is one of the main chemicals which regulates our moods. Some doctors practising in natural medicine believe that amino acid therapy is more effective in some cases than the traditional drugs that are used to treat depression. Eating good sources of protein helps to boost our levels of serotonin and dopamine and this is really important as these help to boost energy, mental clarity, and basically make you feel happier as well as regulate pain, reduce anxiety, initiate deep sleep.

If you see my post on raising levels of serotonin, that may be beneficial in helping prevent AD...

also https://www.psychologytoday.com/blog/th ... ain-health

[Orangeblossom]

On the original study in the OP...Just been reading about homocystiene and that it can be high in some people like vegans / veggies with low protein intake. It seems the B vits might be the issue...wonder how much of this result might be about the people with low protein levels possibly having higher homocystiene, especially when you think about elderly people maybe not cooking much and eating easy to prepare things perhaps...maybe not cooking from scratch and eating as much meat. Not sure but just a thought. It also seems to generally mention in the literature about homocystiene levels being higher in 'poor diets'. Could also be something for veggies / vegans to be aware of...

https://www.ncbi.nlm.nih.gov/pubmed/11053901 Homocysteine levels in vegetarians versus omnivores

https://www.ncbi.nlm.nih.gov/pubmed/23298782 Plasma total homocysteine status of vegetarians compared with omnivores: a systematic review and meta-analysis.

"This is the first systematic review and meta-analysis to appraise a range of studies that compared the homocysteine and vitamin B₁₂ levels of vegetarians and omnivores. The search methods employed identified 443 entries, from which, by screening using set inclusion and exclusion criteria, six eligible cohort case studies and eleven cross-sectional studies from 1999 to 2010 were revealed, which compared concentrations of plasma tHcy and serum vitamin B₁₂ of omnivores, lactovegetarians or lacto-ovovegetarians and vegans. Of the identified seventeen studies (3230 participants), only two studies reported that vegan concentrations of plasma tHcy and serum vitamin B₁₂ did not differ from omnivores. an inverse relationship exists between plasma tHcy and serum vitamin B₁₂, from which it can be concluded that the usual dietary source of vitamin B₁₂ is animal products.."

Basically veggies and especially vegans had higher homocysteine levels.

With those supplementing B Vits might not be such a problem but that might not apply to the elderly in the study. It would be good to have had more info about the overall diet and nutrition really.

[Roamingseer]

@Julie G, thank you for your post. I didn’t notice it until today- wish there was a way to direct posts to individuals that the website would notify them directly, like Strava does by adding an @ before their screen name.

Like you, I am fascinated by the why, but chose to hedge my bets by increasing my protein intake slightly (10g/d) through an added 2tbsp/d of hemp protein, since I do exercise a bit.

I am interested in whatever you find out. Thank you again!