Debunking the vitamin D fad
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Throughout the pandemic, many unproven miracle COVID-19 “cures” emerged, and vitamin D claims have been one of the most persistent. This is not new for the vitamin. It’s been touted in recent decades as a way to “boost” the immune system, improve overall health, prevent a host of diseases, and allegedly even substitute for vaccines.
But as with many internet-popular health “remedies,” the reality is far less flashy and far more nuanced.
What is vitamin D, and why is it important?
Vitamin D is a nutrient that helps the body absorb calcium, which is essential for bone health. In the sunlight, your skin naturally produces vitamin D that is then stored in fat cells until it is used.
The skin pigment melanin absorbs the UV rays necessary for vitamin D production, meaning that more highly pigmented or darker skin produces less vitamin D than lighter skin with the same amount of sun exposure. Thus, people with darker skin are at higher risk of vitamin D deficiency.
Most of our vitamin D comes from the sun. An additional 10 percent to 20 percent of our vitamin D comes from foods like fatty fish (such as salmon), eggs, and mushrooms. Vitamin D supplements are another source of the nutrient for people who are unable to get enough from sun exposure and diet.
Vitamin D deficiency is real, but there’s no epidemic
Some people who promote vitamin D supplements claim that vitamin D deficiency is an epidemic causing widespread health issues. There is little evidence to support this claim. A 2022 analysis of 2001-2018 data found that 2.6 percent of people in the U.S. had severe vitamin D deficiency.
Severe vitamin D deficiency can cause serious health issues, such as muscle weakness, bone loss in adults, and rickets (weak bones) in children. Some people are at higher risk for the deficiency, including individuals with certain disorders that prevent the body from absorbing or processing vitamin D or those with a family history of vitamin D deficiency.
Black Americans have the highest rates of severe vitamin D deficiency at nearly 12 percent. Severe vitamin D deficiency is also slightly higher in the U.S. during the winter when people get less sun exposure. Rates of moderate vitamin D deficiency are higher at 22 percent overall and are highest among Black Americans (49 percent) and Mexican Americans (35 percent).
Although severe vitamin D deficiency exists in the U.S., it is far from common. Most tellingly, conditions that are directly linked to vitamin D deficiency are not widespread. There is no epidemic of rickets, for example, or bone loss in adults.
There’s little evidence that vitamin D supplements improve overall health
Vitamin D supplements have clear, proven positive effects for people with vitamin D deficiency. Other health benefits of vitamin D supplements are less certain.
There is some evidence that the supplement may reduce the risk of fracture in adults with osteoporosis, a condition that causes weak, fragile bones. However, the benefit appears to be limited to people who have low vitamin D levels. In adults with normal vitamin D levels, supplements have no effect on fracture risk.
The largest randomized controlled trial of vitamin D, called VITAL, investigated the effects of vitamin D supplementation in people without an existing deficiency. The study found that vitamin D supplements had no effects on the risk of cancer, diabetes, or cardiovascular disease, including heart attack and stroke. The study concluded that more research is necessary to determine who may benefit from vitamin D supplements.
Independent analyses found that vitamin D supplementation may be associated with a long-term decrease in cancer mortality, but results are mixed and also require more investigation.
A 2021 analysis of past vitamin D trials found no overall health benefits from vitamin D supplements in people with normal vitamin D levels. Most large-scale studies have found no link between vitamin D supplements and lower all-cause mortality (deaths from any cause), except in older adults and those with vitamin D deficiency.
Vitamin D provides modest protection against respiratory infections
Vitamin D is important for immune function, but this is often misconstrued as vitamin D “boosting” the immune system.
Some people falsely believe that taking vitamin D supplements will keep them healthy and prevent infections like the flu or COVID-19. In reality, clinical trials and large-scale studies of vitamin D have found only minimal protective effects against respiratory infections.
A 2021 analysis of 46 trials found that 61.3 percent of participants who took daily vitamin D supplements got respiratory infections during the study periods—compared to 62.3 percent of people who did not take the supplements. A 2024 meta-analysis of 43 trials found no overall protective effect against respiratory infections, but it detected a slight decrease in risk among people who took specific doses daily.
In young children, there is some evidence that vitamin D supplementation may reduce the length of respiratory infections. However, it does not affect the number or severity of infections that children have.
Despite claims that taking vitamin D can protect against COVID-19, two clinical trials found that taking daily vitamin D supplements did not reduce the risk or severity of COVID-19 infections, even at high doses.
Context is key when considering vitamin D’s benefits
None of these studies contradict the well-established evidence that people with vitamin D deficiency benefit from vitamin D supplements. But it’s important to remember that many of the most popular health claims about vitamin D’s benefits are based on research in people with vitamin D deficiency.
Research in vitamin D-deficient populations is important, but it tells us little about how vitamin D will affect people with normal or close to normal vitamin D levels. A closer look at vitamin D research in people without low levels reveals little evidence to support the idea that the general population benefits from taking vitamin D supplements.
For more information, or to learn about your vitamin D levels, talk to your health care provider.
This article first appeared on Public Good News and is republished here under a Creative Commons license.
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It’s Not Hysteria – by Dr. Karen Tan
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Firstly, who this book is aimed at: in case it wasn’t clear, this book assumes you have, or at least have had, a uterus. If that’s not you, then well, it’ll still be an interesting read but it won’t be about your reproductive health.
Secondly, about that “reproductive health”: it’s mostly not actually about reproductive health literally, but rather, the health of one’s reproductive organs and the things that they affect—which is a lot more than the ability to reproduce!
Dr. Tang takes us on a (respectably in-depth) tour of the relevant anatomy, before moving on to physiology, before continuing to pathology (i.e. things that can go wrong, and often do), and finally various treatment options, including elective procedures, and the pros and cons thereof.
She also talks the reader through talking about things with gynecologists and other healthcare providers, and making sure concerns are not dismissed out-of-hand (something that happens a lot, of course).
The style throughout is quite detailed prose, but without being difficult at all to read, and (assuming one is interested in the topic) it’s very engaging.
Bottom line: if you would like to know more about uteri and everything that is (or commonly/unfortunately) can be attached to them, the effects they have on the rest of the body and health, and what can be done about things not being quite right, then this is a good book for that.
Click here to check out It’s Not Hysteria, and understand more of what’s going on down there!
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When supplies resume, should governments subsidise drugs like Ozempic for weight loss? We asked 5 experts
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Hundreds of thousands of people worldwide are taking drugs like Ozempic to lose weight. But what do we actually know about them? This month, The Conversation’s experts explore their rise, impact and potential consequences.
You’ve no doubt heard of Ozempic but have you heard of Wegovy? They’re both brand names of the drug semaglutide, which is currently in short supply worldwide.
Ozempic is a lower dose of semaglutide, and is approved and used to treat diabetes in Australia. Wegovovy is approved to treat obesity but is not yet available in Australia. Shortages of both drugs are expected to last throughout 2024.
Both drugs are expensive. But Ozempic is listed on Australia’s Pharmaceutical Benefits Schedule (PBS), so people with diabetes can get a three-week supply for A$31.60 ($7.70 for concession card holders) rather than the full price ($133.80).
Wegovy isn’t listed on the PBS to treat obesity, meaning when it becomes available, users will need to pay the full price. But should the government subsidise it?
Wegovy’s manufacturer will need to make the case for it to be added to the PBS to an independent advisory committee. The company will need to show Wegovy is a safe, clinically effective and cost-effective treatment for obesity compared to existing alternatives.
In the meantime, we asked five experts: when supplies resume, should governments subsidise drugs like Ozempic for weight loss?
Four out of five said yes
This is the last article in The Conversation’s Ozempic series. Read the other articles here.
Disclosure statements: Clare Collins is a National Health and Medical Research Council (NHMRC) Leadership Fellow and has received research grants from the National Health and Medical Research Council (NHMRC), the Australian Research Council (ARC), the Medical Research Future Fund (MRFF), the Hunter Medical Research Institute, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia, the Western Australian Department of Health, Meat and Livestock Australia, and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk (for weight management resources and an obesity advisory group), Quality Bakers, the Sax Institute, Dietitians Australia and the ABC. She was a team member conducting systematic reviews to inform the 2013 Australian Dietary Guidelines update, the Heart Foundation evidence reviews on meat and dietary patterns and current co-chair of the Guidelines Development Advisory Committee for Clinical Practice Guidelines for Treatment of Obesity; Emma Beckett has received funding for research or consulting from Mars Foods, Nutrition Research Australia, NHMRC, ARC, AMP Foundation, Kellogg and the University of Newcastle. She works for FOODiQ Global and is a fat woman. She is/has been a member of committees/working groups related to nutrition or food, including for the Australian Academy of Science, the NHMRC and the Nutrition Society of Australia; Jonathan Karnon does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment; Nial Wheate in the past has received funding from the ACT Cancer Council, Tenovus Scotland, Medical Research Scotland, Scottish Crucible, and the Scottish Universities Life Sciences Alliance. He is a fellow of the Royal Australian Chemical Institute, a member of the Australasian Pharmaceutical Science Association and a member of the Australian Institute of Company Directors. Nial is the chief scientific officer of Vaihea Skincare LLC, a director of SetDose Pty Ltd (a medical device company) and a Standards Australia panel member for sunscreen agents. Nial regularly consults to industry on issues to do with medicine risk assessments, manufacturing, design and testing; Priya Sumithran has received grant funding from external organisations, including the NHMRC and MRFF. She is in the leadership group of the Obesity Collective and co-authored manuscripts with a medical writer provided by Novo Nordisk and Eli Lilly.
Fron Jackson-Webb, Deputy Editor and Senior Health Editor, The Conversation
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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The Polyvagal Theory – by Dr. Stephen Porges
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Do you ever find that your feelings (or occasionally: lack thereof) sometimes can seem mismatched with the observed facts of your situation? This book unravels that mystery—or rather, that stack of mysteries.
Dr. Porges’ work on this topic is, by the way, the culmination of 40 years of research. While he’s not exactly a household name to the layperson, he’s very respected in his field, and this book is his magnum opus.
Here he explains the disparate roles of the two branches of the vagus nerve (hence: polyvagal theory). At least, the two branches that we mammals have; non-mammalian vertebrates have only one. This makes a big difference, because of the cascade of inhibitions that this allows.
The answer to the very general question “What stops you from…?” is usually found somewhere down this line of cascade of inhibitions.
These range from “what stops you from quitting your job/relationship/etc” to “what stops you from freaking out” to “what stops you from relaxing” to “what stops you from reacting quickly” to “what stop you from giving up” to “what stops you from gnawing your arm off” and many many more.
And because sometimes we wish we could do something that we can’t, or wish we wouldn’t do something that we do, understanding this process can be something of a cheat code to life.
A quick note on style: the book is quite dense and can be quite technical, but should be comprehensible to any layperson who is content to take their time, because everything is explained as we go along.
Bottom line: if you’d like to better understand the mysteries of how you feel vs how you actually are, and what that means for what you can or cannot wilfully do, this is a top-tier book
Click here to check out Polyvagal Theory, and take control of your responses!
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Practical Programming for Strength Training – by Mark Rippetoe & Andy Baker
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Strength training is an important part of overall health maintenance, but it can be hard to find a good guide to progressive strength improvement that isn’t a bodybuilding book.
This one gives a ground-upwards approach, explaining small details to even quite basic things, before taking the reader through to more advanced progressions, and how to get the most strength-building out of each exercise over time.
As such, this is a good book for anyone of any level from beginner to quite experienced, and you can hop in at any point since there are always catch-up summaries and/or reiterations of the previous concepts that we’re now building on from.
The authors do also talk nutrition, hormones, and so forth, but most of it is about the exercises and the progressions thereof.
There is a slightly patronizing chapter towards the end, about “special populations”, for example offering “novice and intermediate training for women”, but it doesn’t take away from the majority of the book, as the exercises don’t care about your gender. Muscles are muscles, and we all start from wherever we are. Yes, testosterone boosts muscle mass, but let’s face it, there are a lot of women in the world who are stronger than a lot of men.
One thing to bear in mind is that a lot of this is barbell training, so you will need a barbell (or access to one at a gym). If purely bodyweight training is your preference, or perhaps some other form of weightlifting (e.g. kettlebells or such) then this isn’t the book for that.
Bottom line: if strength training is your focus and you like barbells, then this is a great book to take you quite a way along that road.
Click here to check out Practical Programming For Strength Training, and get stronger!
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Missing Microbes – by Dr. Martin Blaser
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You probably know that antibiotic resistance is a problem, but you might not realize just what a many-headed beast antibiotic overuse is.
From growing antibiotic superbugs, to killing the friendly bacteria that normally keep pathogens down to harmless numbers (resulting in death of the host, as the pathogens multiply unopposed), to multiple levels of dangers in antibiotic overuse in the farming of animals, this book is scary enough that you might want to save it for Halloween.
But, Dr. Blaser does not argue against antibiotic use when it’s necessary; many people are alive because of antibiotics—he himself recovered from typhoid because of such.
The style of the book is narrative, but information-dense. It does not succumb to undue sensationalization, but it’s also far from being a dry textbook.
Bottom line: if you’d like to understand the real problems caused by antibiotics, and how we can combat that beyond merely “try not to take them unnecessarily”, this book is very worthy reading.
Click here to check out Missing Microbes, and learn more about yours!
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Cherries vs Blackberries – Which is Healthier?
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Our Verdict
When comparing cherries to blackberries, we picked the blackberries.
Why?
In terms of macros, cherries have more carbs while blackberries have more protein and fiber. The protein of course is a tiny amount and an even tinier difference, and/but it’s worth noting that the fiber isn’t, and blackberries have more than 3x the fiber. So, a win for blackberries in this category.
In the category of vitamins, cherries have more of vitamins A, B1, B2, and B6, while blackberries have more of vitamins B3, B5, B9, C, E, K, and choline. Another win for blackberries.
When it comes to minerals, cherries have a tiny bit more potassium, while blackberries have considerably more calcium, copper, iron, magnesium, manganese, phosphorus, selenium, and zinc. Another easy win for blackberries.
Both fruits have abundant antioxidants, but as many are different, and comparison between them becomes more subjective than we have room for here.
In short, enjoy either or both, but we say blackberries win overall on macro- and micronutrients!
Want to learn more?
You might like to read:
Cherries’ Very Healthy Wealth Of Benefits
Take care!
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