The FastDay Forum

I have just written a long post with references to scholarly articles and it mysteriously disappeared when I went to preview it. Grrrrhh. I will come back later on my desktop to add my links, I daren't go through it all again on my iPad.

Has anyone looked at the issue of increased osteoporosis risk for postmenopausal women, as a result of :-
reduced calcium intake during fasting
Weight loss reducing bone mass
Reduced igf-1 levels increasing bone loss
Imbalance of dietary factors, such as relatively high animal protein and reduced calcium intake on fast days... ?

It seems that there are several factors that could be increasing the risks of future fractures...

Interestingly, high calcium levels are linked to improved weight loss.

Steps to reduce increased risk of osteoporosis could include:-
Weight bearing exercise
Increase intake of dairy products and leafy green veg, also higher levels of alkalising vegetables to offset acid effect of animal proteins
Supplementation with calcium and vit D

I am particularly interested in trying to understand what is going on with IGF-1, which we are trying to lower the levels of to reduce the effects of aging, but it seems that low levels increase the rate of bone loss?

I am having good results with weight loss on this way of eating and wish to continue to maintenance, but really want to understand and limit any possible negative consequences.

Any thoughts?

Interesting topic. http://www.marksdailyapple.com/calorie- ... bone-loss/ is worth a read, there's a study at http://www.ncbi.nlm.nih.gov/pubmed/8530611 in young women which looks to separate out pH effects during a short total fast.


em.endojournals.org/content/84/3/883.full is also in young women but concludes :-
"This report is the first to demonstrate that bone turnover falls rapidly with acute caloric deprivation in normal women. RhIGF-I administration uncouples bone formation in this setting by significantly increasing bone formation, but not resorption. These data suggest a novel use of rhIGF-I to selectively stimulate bone formation in states of undernutrition and low bone turnover."

Thanks for the links Phil.

here are the articles that I had meant to include in my first post

Bone, Body Weight and Weight Reduction: What Are the Concerns? http://jn.nutrition.org/content/136/6/1453.full

the Calcium story:

Weight loss and calcium intake influence calcium absorption in overweight postmenopausal women
http://www.ncbi.nih.gov/pubmed/15213038

Calcium supplementation in postmenopausal women to reduce the risk of osteoporotic fractures.
http://www.ncbi.nim.nih.gov/pubmed/21289325

Dairy calcium intake, serum vitamin D, and successful weight loss
http://ajcn.nutrition.org/conent/2010/0 ... 9355.short

Cardiovascular risks with calcium and vitamin D: re-analysis of data
http://www.npc.nhs.uk/rapidreview/?p=3859 - unclear implications

The protein story:

Diets higher in Dairy Foods and Dietary Protein Support Bone Health during Diet- and Exercise-Induced Weight Loss in Overweight and Obese Premenopausal women http://jcem.endojournals.org/content/97/1/251.abstract

Amount and type of protein influences bone health http://ajcn.nutrition.org/content/87/5/1567S.abstract

Excess Dietary Protein Can Adversely Affect Bone http://jn.nutrition.org/conent/128/6/1051.full = need for consumption of alkali-rich foods

Dietary protein and skeletal health: a review of recent human research
http://www.ncbi.nim.nih.gov/pubmed/21102327

My conclusion? We need to exercise, using weights. We need to have good dietary sources of calcium and plenty of vegetables. We need to get out in the sunshine. I'm uncertain at this point as to whether additional supplementation with calcium and vitamin D is a good idea.

I still feel that I haven't got to the bottom of the IGF-1 story. It doesn't seem to make sense to me that lower levels are considered to be anti-aging but at the same time are making bones weaker. It is a concern when considering 5:2 as a lifetime commitment. Maybe it is all tied in with protein, hormones, vitamins, minerals, insulin levels....

There's no vitamin D to be had outside at these latitudes for a couple of months, so Vit D supplements are probably a good idea.

I find dairy products cause digestive problems and if I do have cheese, which I love, I then have to ... er... up the roughage considerably. So I have to rely on daily calcium tablets and lots of veg to keep my bones in order. Been forgetting to take the calcium tablets when missing breakfast so making a conscious effort to ensure i take them at lunch time. I do body pump at the gym and do Dr M's HIT by jogging on the spot. Haven't noticed any problems with my fingernails since starting last August so hope that bones OK and that 5:2 is helping me get the most nutrients out of what I eat.

[carorees]

I think you have to think of IGF1 as being something you can have too much of and too little. You need to keep to the middle ground (like so many things). Also remember that IGF1 is a surrogate marker for activity at different pathways, e.g. mTOR so that needs to be looked at in connection with bone turnover. Parathyroid hormone changes are if course also important.

Lastly we are not really undergoing that severe a calorie deprivation on a weekly basis so any reduction in bone turnover on a fast day is likely compensated for on feast days.