Simon Bowles
Lecturer in Nutrition at Sheffield Hallam University & PhD student at the University of Sheffield investigating the clinical response to high dose vitamin D supplementation in postmenopausal women.
Location Sheffield, UK
Activity
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Yes, an excellent point. Some BAME groups tend to have much poorer uptake of supplements than Caucasians. @ChrisA
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Simon Bowles replied to Simon Bowles
You’re very welcome.
Thank you for your comments.
Simon.
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Simon Bowles made a comment
Ok, it's time for me to sign off from this run of the course. I am sorry if you had questions that I didn't manage to respond to. I do try to get round them all, but it's not always possible.
Thank you all for your discussions over the last few weeks. It has been a pleasure interacting with you all.
From reading the comments below, I am glad that most...
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@CarysSwanwick Hi Carys.
The confusion is my fault. I should have put the 'fractional' amount of calcium absorpbed decreases as dietary calcium intake increases.
So, the more calcium intake the less of that calcium we absorb as a fraction. The less calcium intake, the more of that we relatively absorb.
The body is clever and so upregulates our...
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Louise - You might find this section from the BNF useful: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html?limitstart=0
Regarding your question about increases in protein intake. This is hotly debated. My only concerns about higher protein intake in older adults in the effect on kidney function (particularly where...
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Mike, the review that you have posted is a very sensible one. I agree with it's conclusions.
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I believe that in time we will identify both biological and environmental reasons for the disproportionate deaths seen in those from BAME backgrounds - it will not just be (if at all) to do with vitamin D.
In Summary:
Vitamin D, like other nutrients, should not be seen as a ‘magic bullet’ to beat COVID-19. The scientific evidence base is just not there... -
The strongest evidence based research studies are randomised controlled trials. Indeed, the largest RCTs carried out to date for the prevention and treatment of non-bone health disease (e.g. Cancer, type 2 diabetes and cardiovascular disease) with vitamin D have shown null results - no beneficial effect on type 2 diabetes progression, no beneficial effect on...
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e.g. The most important point related to COVID-19 that I will make is that the carrier proteins that carry vitamin D in the blood are what we call acute phase reactants. Acute phase reactants are inflammation markers that exhibit significant falls in concentration in the blood during inflammation. This is the case of albumin and vitamin D binding protein (the...
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Arguments against a direct role of vitamin D in the prevention and/or treatment of COVID-19:
1. The mechanisms for how vitamin D helps to fight viral infections, such as SARS-CoV-2, are simply based on speculations about presumed mechanisms from an extremely limited evidence base.
2. We have been here before with vitamin D! A few years ago, perhaps...
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Thank you so much for your comments on this part on the thread. I really liked reading them. You all make excellent points and I cannot tell you what is absolutely correct and what isn't. We just don't know enough at this stage, but in time we will. There are lots of studies now underway, particularly randomised controlled trials which are the strongest study...
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@GuyCowley Yes, kippers are on average probably the best source. All oily fish contains vitamin D, but just how much can vary quite widely depending on geographical location.
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Simon Bowles made a comment
A little bit off topic...but I have a very topical question for discussion.
Does anyone have any thoughts on the recent reported link between COVID-19 and vitamin D?
I’ll give you my thoughts (for those interested) at the end of the week. Please do post your thoughts below. There are no right or wrong answers, but I'm very interested to listen to...
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The good thing about vitamin D is that it is actually very difficult to make someone toxic. You would have to take very high doses over a prolonged period of time.
We have very efficient degradation pathways for vitamin D and excess is readily excreted.
But, whether there is any additional benefit in taking amounts above the RNI is very much debatable.
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I can comment on some of those...
Age - Older people actually have a better dietary intake of vitamin D (with and without supplementation) than younger adults. We have done work on this in Sheffield.
Ethnicity - South Asians have a poorer dietary intake of vitamin D than Caucasian counterparts. They also have a poorer use of...
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The RNI is set at 10 micro grams per day as this is the amount that is seen as enough to keep 97.5% of the population out of the deficiency threshold. So there will be a lot of people who don’t reach this level of intake but are still not deficient.
This may be for reasons that you suggest, such as the contribution of sunlight from April to October and...
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It does vary. It’s depends on where the fish is caught too!
But generally oily fish is the only really significant dietary source of Vitamin D.
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The RNI in the UK is set at 0.75g of protein per kilogram of bodyweight per day for adults.
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Hi Martin. Although the thyroid gland and parathyroid glands are neighbours anatomically, they have very different physiological jobs to do and are unrelated.
The thyroid glands generally help govern metabolism throughout the body, but the parathyroid glands (via parathyroid hormone) help govern calcium levels in the blood.
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Simon Bowles replied to Linda F
In short, for most people probably not. There may be certain circumstances where people might do something extreme (e.g going from being sedentary to becoming a competitive weight lifter or something). Or if some physiological abnormality was corrected.
But generally, after around the age of 35 it’s then about maintaining what you have and in later years,...
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Anne, I agree with your GP.
That is the general rule!
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Hi George.
Yes, I'm very fussy with the use of 'facts'. I believe that, generally, if someone is presenting something as 'fact' they have very little understanding of science.
I'm particulaly fussy with my students when they write "it has been proven that..."
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Hi Malcolm.
You are absolutely right. It is almost an impossible task to quantify.
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Hi Lou,
Nutrient Reference Values are EU recommendations for the daily ntake of vitamins and minerals based on current understadning. The NRV replaced the Recommended Daily Allowance (RDA) for vitamins and minerals only back in 2014.
NRV's are set for the purposes of food labelling and are EU guidance levels on the daily amount of vitamin or mineral...
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Hi Mike,
I am not aware of any studies that have quantified the effect of alcohol intake on calcium absorption in this way. Most studies have just reported an inverse association between alcohol intake and fractional calcium absorption and/or serum calcium.
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I think for most people magnesium deficiency will not be a problem (around 85% of people in the UK have magnesium intakes at or above the reference nutrient intake of 300mg for males and 270mg/day for females). Magnesium is found in lots of different foods too.
It also seems that magnesium intakes are better in older vs. younger people and better in...
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Hi Carys.
This is an interesting question. It is not an easy one to answer.Magnesium is important for bone health and enzyme activity. It is thought to have effects on osteoblasts, effects on hydroxyapatite crystal formation and also plays a role in the regulation of calcium homeostasis through interactions with PTH and vitamin D.
I think there is a...
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Hi Daniela.
Thanks for your comment. Yes, unfortunately there is a genetic link too. We would say that there is a genetic susceptibilty to osteoporosis and so like lots of health and disease outcomes, we could say that we need to 'pick our parents well!' People with a slight consitution do seem to be at higher risk.
However, just because a parent (or...
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@gilliantennant We see lots of older people who are vitamin D deficient (well actually across all age groups). It certainly is likely due to lifestayke factors, such as not getting a healthy and varied diet and not getting unprotected sunlight exposure.
Regrding injetions... It may be that there are malabsorption concerns and intramuscular injections are a...
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Simon Bowles made a comment
Here are some other factors to consider for calcium absorption:
- High sodium intake increases the amount of calcium that we excrete in our urine
- High protein intake also increases urinary calcium excretion and was therefore thought to negatively affect calcium status. However, there is also research to suggest that high protein intake also increases...
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Simon Bowles made a comment
Last week I mentioned (somewhere) that I would put up some more information about calcium absorption and bioavailability. There's an awful lot to summarise but here are some points about foods that may affect calcium absorption:
- The fractional amount of calcium absorbed decreases as dietary calcium intake increases
- As we age we absorb less calcium -...
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Hi All,
just some thoughts to add:
DRVs (or dietary guidelines) are ‘recommended’ values and are therefore guidelines at a population level.
There are many individual differences within a population (that extend beyond gender, age, ethnicity, disease status) and only now are we beginning to understand the potential importance of nutrient-gene...
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Simon Bowles made a comment
People may find these British Dietetic Association Information on Osteoporosis and calcium and Vitamin D helpful:
They also have other food...
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Yes, it is used interchangeably and depends the country or institution really.
There rule is 10 micrograms = 40IU.
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Hi Sarah.
There are actually lots of types of vitamin D in the body. The form of vitamin D that we predominantly get from the diet is the same as what we make in our skin - Vitamin D3.
However, this vitamin D3 needs to be converted to the active form - this is done through two sequential steps. First the vitamin D3 is transported (bound to vitamin D...
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Yes, Linda. We have done lots of work here in Sheffield on vitamin D levels in Obesity. People living with obesity do tend to have lower levels of vitamin D than normal weight counterparts.
This is due to 'volumetric dilution'. Basically the vitamin D is still in the body, but it is just diluted by the higher body mass (particularly the higher fat mass...
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Simon Bowles made a comment
There is so much that affects our ability to synthesise vitamin D in the skin. Vitamin D is specifically snthesised in the skin using UVB wavelengths of light.
it is affected by:
- Time of year: in the UK we cannot synthesis vitamin D in the skin between October to the end of March. The sun is never high enough in the sky.
- Time of day: even in the summer,... -
I really like this video from Prof. Powers. I think that she explain some very difficult concepts quite nicely. I think it is really good for people to see just how much work goes into creating intake guidelines for a particular nutrient and how thorough the process is. Of course, this does not mean that it is perfect!
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Simon Bowles made a comment
Welcome to week 3 everyone. I am biased, but this is my favourite week! :)
I will keep trying to get through as many questions/comments as I can. I am sorry if I have missed anyone's questions so far...there have been a really high number in this run, but I have tried to get through as many as I can.
Thank you all so far for your interest and the role...
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Hi Jasmine.
Yes, Men typically have a higher bone mineral density than women and so they will typically have a greater bone strength. Genetics and hormones play a role, including the higher muscle mass.
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@SehrShahid I absolutely agree.
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@CarysSwanwick Yes, absolutely right. Of course, nothing is certain and genetics play a role too, but what you say is correct.
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@LOUISEWOODS Yes, and I think we see this kind of resistance in the National Child Measurement Programme too.
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Simon Bowles replied to Hugh Sussens
Thanks Hugh.
That's really nice feedback to receive!
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Simon Bowles made a comment
I agree from what the literature seems to tell us and also from my own experience too. When I exercise (in a way that I have found suits my needs) I have much less stiffness and pain in the hip joint.
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@MaryHartley Of course, It may not 'build' bone because there isn't the strain on bone caused by walking that is required, but much like the water aerobics example it may help to stimulate blood and nutrient flow to bone cells helping to maintain a healthy environment for your bones. Doing something is much better than being sedentary.
As you will know,...
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Simon Bowles replied to Simon Bowles
@GitaMistry Yes, as we age the internal environment is increasingly more conducive to inflammation.
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It's amazing. The hypothetical mechanism for how bone senses this stimuli and then responds is also equally fascinating. It's called the 'mechanotrasduction' or 'fluid flow model'.
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Simon Bowles made a comment
This section makes me wonder about the lifestyles of many children, adolesence and young adults in modern society. How active we are in younger life can have very important and life long effects.
We only have the opportunity to build significant bone significantly in the first 30-35 years of life, when we reach our peak bone mass. After this, we gradually...
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Simon Bowles replied to [Learner left FutureLearn]
Absolutely.
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Simon Bowles replied to Andy Payne
Hi Andy,
Thanks for your challenging questions. I am not a sports science expert and happy to be corrected, but just some comments to you questions.
1. I think Mike may be referring to vasoconstriction in the nonactive tissues at the start of exercise to direct blood towards the working muscle.
2. I absolutely agree, there is a decline in the...
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Simon Bowles made a comment
Continued from below...
You don’t necessarily have to change the exercise regime once established, because by maintaining the new regime in the long term you have reset the ‘baseline’ level of musculoskeletal health.
This improved level of musculoskeletal health then will be the baseline (or your ‘normal’ level) moving forward whilst ever you maintain...
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Simon Bowles made a comment
I think because everyone has different levels of physical activity and levels of time spent sedentary that it's important to comment and say that the impact of any exercise is all relative to the amount of exercise that you currently do.
If you already exercise lots with lots of varied exercise including both aerobic and resistance type exercise and also...
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Hi Michael,
We focus on how we can use diet to maintain musculoskeletal health next week.
It sounds like the Zolendronate has worked very well for your wife.
Simon.
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Simon Bowles made a comment
Age does have an effect on the ability of bone to respond and so the response of bone to exercise is poorer as we age.
Although, we cannot replace the muscle fibres that we lose with age, we can still cause the fibres that we have remaining to grow. The force exerted on the bone by a collection of larger muscle fibres then naturally exerts a larger strain...
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A holistic approach is definitely a good idea.
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Hi Leigh.
When we talk about osteoporotic fracture in older people what we really mean are 'fragility' fractures - so low impact fractures resulting from falls from a standing height.
Highly active children just have more opportinity to fracture than children who are not so physically active and usually they would only frature from what would be...
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Simon Bowles made a comment
I think people have a lot of questions about what type of exercise is good for building bone and so I think a lot of people will find these links useful.
These links give an overview of general exercises that are suitable for maintaining bone health. Of course everyone is different and not all will be suitable for everybody.
This is exercise advice from...
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Simon Bowles made a comment
After watching this video, people often have questions about water exercises (e.g. aqua aerobics) and how that fits in with being beneficial to bone.
In order to make bones stronger, the load applied to the bone must be increased in some way through exercise. It's almost like shocking the skeletal system by increasing the load quickly.
The most effective...
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You are absolutely right. They do.
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Simon Bowles made a comment
Welcome to week 2 everyone. Hope you enjoyed last week and that you found it interesting (if not a liitle gloomy!). I hope you managed to learn something new. If you did find it a little gloomy, don't worry because this week we begin to focus on things that can help to maintain and potentially improve our musculoskeletal health! We begin with physical activity...
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Simon Bowles replied to Simon Bowles
You're welcome!
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Hi Catherine,
1. This is highly debated. Even if the mechanism that you describe does occur, it is unclear just how significant a contribution this would make to overall skeletal health. My personal opinion (although others will certainly disagree) is that it will not contribute that much.
2/3. Yes, there are several ways to measure calcium in the...
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@MichaelMoller Yes, that’s right, the bones respond to the additional strain.
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Simon Bowles replied to Simon Bowles
@LeslyeSlater Absolutely. There are many different combinations that are available to purchase over the counter.
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Simon Bowles replied to Simon Bowles
Yes, absolutely. In order to interpret a blood calcium you really need a PTH measurement too.
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This is usually to do with the amount of trabecular bone (the spongy type of bone with a honeycomb structure found enclosed within the bone itself) that a bone contains.
The trabecular bone has a large surface area and is much more metabolically active (and therefore more suseptible to deterioration) than compact bone. Therefore, bones with a high...
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Simon Bowles replied to jacqueline lowe
Yes, absolutely. A very controvesial area.
There are different ways of taking HRT and there are varying benefits and risks attached with each.
HRT largely helps to restore oestrogen levels that is lost at the menopause. Oestrogen is bone protective; it is good for bone. It helps to maintain bone health as it slows the rate of bone...
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Simon Bowles replied to Simon Bowles
@CarolynE thanks for the heads up.
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Thanks for sharing that Lillian.
Your daughter seems to have very similar issues to those that I have! Her story sounds remarkabley similar to mine.
Simon.
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Simon Bowles made a comment
Thank you all for your comments.
It is great to see how positive all of your comments have been so far. This group of learners do seem to be a cohort who are prepared to receive the messages conveyed within the content of the course in a very positive way; for me that is great to see (this has not always been the case!).
We do focus on what we can do to...
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Hi Jackie.
I am glad that you mention obesity here.
It is actually a bit of an anomoly when it comes to bone health, because people living with obesity tend to have a higher bone mineral density and fracture less than leaner people (apart from at the ankle). So obesity does seem to protect against fracture.
We will learn next week when we look at...
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Simon Bowles replied to Andy Payne
I really like the final part of your comment:
"Maybe we should not passively accept our own decay but rather be active in ameliorating it?"
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Simon Bowles replied to Simon Bowles
The calcium and vitamin D combinations that you refer to (commonly known as Adcal) are usually taken by people on bisphononate treatment for osteoporosis (these treatments are only licenced with calcium and vitamin D supplementation). Often these are not well tolerated (stomach upsets, etc…) and so some people might chose to just take vitamin D and try to...
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Simon Bowles replied to Simon Bowles
Most calcium (whether from supplements or food sources) is absorbed at the intestine across what is known as an electrochemical gradient (basically like diffusion, moving from a higher concentration in the lumen of the intestine to a lower concentration in the enterocytes). This is most efficient with good calcium intakes. This process is thought...
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Hi Hugh,
I am not an expert on tendons, but I think that it means that they are inelastic relative to other soft tissues. I think different tendons do have different properties, but in general they are to a greater degree non-elastic because they transmit the contractile movement of muscle to move bone at joint. So to prevent energy loss they are generally...
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The skeleton really is amazing.
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Simon Bowles replied to Linda F
Absolutely agree that exercise can certainly help.
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Simon Bowles replied to Simon Bowles
In short, yes, there are certainly things that can be done, particularly appropriate exercise and diet.
There are drugs available to help slow the decline in bone mineral density and bone strength in people suffering from osteoporosis. These are very effective treatments, but often take a long time to have the desired effect on bone....
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Simon Bowles replied to Linda F
We will discuss this next week, but this also applies to bone heatlh too.
We accrue bone up to about the age of 30-35 (depends on which part of the skeleton we are looking at) until we reach what is called 'peak bone mass'. After that there is a very steady decline in bone mineral density, even in healthy people.
So its so so important to be as activity...
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Hi Valerie,
We do focus on what we can do to maintain musculoskeletal health as we age in the coming weeks - it is not all bad news.
This week is to try and give people an underlying baseline knowledge of what happens to our bodies as we age and then over the next couple of weeks we look at what we can try and do about it. :)
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Simon Bowles replied to Jean C
We do look at general ways to help to maintain muscluoskeletal heath with physical activity next week, but our current understanding of the process of denervation in old people is still quite poor and so unfortunately specific interventions are not yet there.
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Simon Bowles made a comment
A bit of a summary and additional explanation for anyone interested....
We cannot replace the muscle fibres that we lose with age. However, we can still cause the remaining fibres that we have to grow.
By building up these existing muscle fibres (and increasing overall muscle strength) in key areas (e.g. Arms) then this might allow an older person to be...
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Simon Bowles replied to Diane Smith
You're welcome.
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Simon Bowles replied to Simon Bowles
No problem. :)
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Simon Bowles replied to Simon Bowles
You're very welcome.
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Simon Bowles replied to Simon Bowles
As we age the increase in PTH (seen in lots of older peple) is to try to keep the calcium levels in our blood within a very narrow normal range. It is absolutely essential that calcium is within this normal range for us to live (for our muscles to contract properly and heart to be able to beat and for a whole range of other physiological reasons...
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Hi Nicky,
I am not aware of its use in intermediate care in the community. They are typically carried out by the GP as this allows them to assess whether the individual should be forwarded for further investigation by specialist teams.
Simon.
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Simon Bowles replied to Diane Smith
Taking collagen is a little more controversial, with research showing a very mixed bag of results.
The body can produce collagen (it is organic). Therefore, it may be more about what the body does with the collagen that it makes (e.g. the quality of the collagen matrix in bone that is built), rather than the body not having enough collagen...
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Simon Bowles replied to Diane Smith
Yes, although absorption might decline as we age, calcium supplements are still absorpbed. They are not always well tolerated, however, and compliance can be quite poor. Estimates vary and it depends on the individual, but somewhere around 30% of the calcium that we ingest is actually absorbed (known as bioavailability). There are lots of dietary factors that...
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Simon Bowles made a comment
FRAX is a very interesting tool. Do take a look at the link to find out more information. It is here in case anybody missed it in the text:
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Simon Bowles replied to jacqueline lowe
Hi Jacqueline.
Oestrogen is of course another very important hormone to consider when we are thinking of why there is a remodelling imbalance (an imbalance between the osteoblasts and osteoclasts) as we age.
Oestrogen binds to oestrogen receptors on osteoblasts and encourages osteoblast formation. Oestrogen also inhibits osteoclast formation and it...
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Simon Bowles made a comment
Why does Parathyroid Hormone (PTH) tend to increase as we age?
A major role of PTH in the body is to keep blood levels of calcium in the normal range and so more PTH is secreted in response to falling blood levels of calcium. PTH seeks to increase that blood calcium level through maximising he absorption of calcium at the intestine, retaining more calcium...
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Simon Bowles made a comment
Why the imbalance between osteoclasts and osteoblasts as we age?
The answer is multifactorial and quite complex.
Osteoclasts are produced from haematopoietic stem cells. These cells produce macrophages, which under the right conditions, begin to fuse together to produce pre-osteoclasts and eventually they become mature osteoclasts. There are lots of...
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Simon Bowles made a comment
Hi everyone,
Below is a summary of what happens to bone in osteoporosis for anyone interested...
Bone is a dynamic organ - it is constantly changing and responding to the external environment and the body's internal environment. In order to respond appropriately, a process known as the bone remodelling or bone turnover cycle is constantly occurring...
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Simon Bowles replied to jack curtis
@LeslyeSlater Thanks for that detailed reply Leslye!
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Simon Bowles made a comment
Hello Everyone! I am looking forward to interacting with you over the coming weeks. I will reply to as many of your comments and queries as I can. I do hope that you all enjoy the course.
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Simon Bowles made a comment
I thought that I would share my own story and thoughts...
At 33, I have osteoarthritis in both hip joints. This has been caused by hip dysplasia. I had no idea about this until my late twenties, but basically this means that my femoral heads are too big for my hip sockets. This has caused cartilage in the joints to wear away at an accelerated rate. My right...
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Simon Bowles replied to Carolyn I
Vitamin is predominantly found in two main forms; D2 and D3.
D3 is the 'animal form' and is therefore the form that is synthesised in the skin when exposed to sunlight. D2 is the fungal form and is found in mushrooms for example.
They are both pretty much eqipotent for humans (they do pretty much the same job).
Most supplements in the UK use D3 -...
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Simon Bowles replied to Kathleen Duffy
Thanks, Kathleen.
Glad you enjoyed the course. :)
