Lecture 3- 17 Sept 2010
Osteoporosis
Today
More on nutritional approaches to osteoporosis
Functional foods-approaches to osteoporosis
Nutraceuticals –approaches to osteroporosis
I. More on nutritional approaches to osteoporosis
A novel treatment for patients recovering from hip fractures is to give protein supplements coupled with adequate amounts of micronutrients
In one study- clinical outcomes and bone mineral concentration were improved in patients who were given 250 ml daily of a liquid supplement containing 20 grams of protein, 525 mg of calcium, 750 IU of vitamin A, and 25 IU of vitamin D for an average of 38 days
Role of each of these nutrients in osteoporosis
Issue of protein causing osteoporosis
-although high calcium intakes are not significantly affected by high protein intake, low calcium intakes are not generally sufficient to offset a high protein intake
also important is the total intake of protein in the diet
low levels of serum albumin (define) negatively affects the transport of calcium
animal protein increases urinary losses of calcium-fracture patients acutely- ie with each meal containing large amounts of animal protein-why?
however, soy protein has little impact on urinary calcium losses-why?
In other words is it really the animal protein vs plant protein? What sort of experiments could be done to answer this question?
Having said all that-why does the protein supplement (250 ml daily of a liquid supplement containing 20 grams of protein, 525 mg of calcium, 750 IU of vitamin A, and 25 IU of vitamin D for an average of 38 days) work?
I. More on nutritional approaches to osteoporosis
Phosphorous
High dietary phosphorous intake increases the level of a hormone in the body called parathyroid hormone(PTH)
-PTH which reduces vitamin D production in the body and hence intestinal absorption of calcium
-note recall that vitamin D can be produced by ultraviolet light from the sun
however increased dietary phosphorous has an opposing effect on calcium balance- as dietary phosphorous increases the amount of calcium lost in the urine decreases-controversial as to whether this may offset adverse effects on calcium absorption and bone metabolism in healthy adults- what about unhealthy adults?
The phosphorous:calcium ratio may be more important than the phosphorous level alone
However a diet high in phosphorous (1700 mg/day) and low in calcium (10 mmol/day)- resulted in an increase in PTH secretion- if extended over a long period of time it is suspected that this common dietary pattern could lead to an unfavourable content of bone calcium
Calculation –mmol/day convert to mg/day
1 mol = 40 grams
In contrast prolonged dietary phosphorous deficiency can result in low serum levels of phosphorous- the consequence of this is resorption of phosphorous from bones
-this is a problem because of much of the bone structure is due to calcium phosphate complex
II. Functional foods-approaches to osteoporosis
Define – a functional food is one that naturally or by addition contains (a) chemical entity(ies) (atom(s) or molecule(s)) that confer(s) a therapeutic benefit beyond that ascribed to the possible nutritional value of that(those) entity(ies)
- a example is fish which contains fatty acids that lower blood triglycerides
high calcium foods such a milk and other dairy products- are these really functional foods?
designer functional foods- calcium added to orange juice- orange juice is naturally low in calcium- so is this a functional food?
Avoiding foods like alcohol(a food?) caffeinated foods, high animal protein intake etc-concept of negative functional foods
III. Nutraceuticals –approaches to osteoporosis
Define – a nutraceutical is a concentrate of animal or plant that contains (a) chemical entity(ies) (atom(s) or molecule(s)) that confer(s) a therapeutic benefit beyond that ascribed to the possible nutritional value of that(those) entity(ies)
- a example is fish oil which contains fatty acids that lower blood triglycerides-
- nutraceuticals frequently come in capsule or tablet form and thus take on the similarity to pharmaceuticals-
- what differences/similarities might there be between nutraceuticals and pharmaceuticals?
potential advantage of nutraceutical over functional food is one of concentration- ie get more of an active agent per volume- what might be the potential disadvantages of nutraceuticals over functional foods?
Potential advantages/disadvantages of a nutraceutical over a traditional pharmaceutical?
Calcium and vitamin D supplements (alone or in combination in a given tablet)-are these truly nutraceuticals
What about concept of negative nutraceuticals-what does this mean to you?- what possible examples are there for negative nutraceuticals for osteoporosis
Next 2 lectures- atherosclerosis