on May 6, 2010
My criticism of Dr. Holick's first book on Vitamin D was that he neglected to provide dosage guidelines. His new book contains Vitamin D dosage guidelines--and lots of them!
Holick has dosage advice for pregnant mothers, children, and adults. He talks about how much he advises his patients to take when they are very low, and how much to take when they have got their levels up to healthy levels. He even says how much he personally takes.
Dr. Holick discusses the different ways Vitamin D can be absorbed -- sun, supplements, food, and Vitamin D lamps.
He also explains how common health problems (obesity); skin color (dark); location (north); season (winter); age (elderly); gut health (poor); drugs (prednisone); and rare diseases interfere with Vitamin D absorption. It is surprising to read he recommends obese people take 2-3 times the Vitamin D of non-obese people. Does the Government do that? No. Why? He does the research and it doesn't.
Holick believes the Recommended Daily Allowance (RDA) of Vitamin D is far too low; it's based on poor outdated research from 50 years ago. Government employees and average doctors are extremely ignorant about Vitamin D, unfortunately. Fortunately, however, they do blood tests for their patients, and then they're converted.
You may not know that the effectiveness of the sun for Vitamin D depends on where it hits your body and how much of your skin is exposed to the sun. Your face is the least effective part at absorbing the sun for Vitamin D; so all those walks in the spring, fall, or winter you might take aren't as valuable as you might think. (I'm thinking of getting a new Vitamin D lamp that Holick has tested.)
The good news this book gives is it doesn't take a long time or cost a lot to fix the very common health problem; rather, it's fairly quick and inexpensive to get your Vit-D level up. In as little as two months through sun (free) or supplements ($25) you could get healthy Vit-D levels. Furthermore, high levels in the summer can take you through the entire winter.
If you already have Holick's first book like I do and are wondering about getting the new one, I suggest you get it. This one has new material because Holick is still on the cutting edge of Vitamin D research. You can never know too much.
I'm not sure Holick mentioned it (don't recall reading it in his book, and it's not listed in the Index), but there is some research that indicates Vitamin A taken with Vitamin D can lower Vitamin D absorption.
Despite being so knowledgeable about Vitamin D and ahead of just about everyone, Holick is behind on the research about bright light boxes for circadian rhythm and SAD therapy. New research has shown they can cause eye damage. It can takes years before the blindness comes. The elderly are at greater risk. Green light therapy has been shown to be safer than bright light and blue light but just as effective. (The military did its own tests and is now using green; Google green light therapy to learn more.)
on April 26, 2010
Learning about vitamin D from Michael Holick is like learning the art of magic from Harry Houdini. Greatly reducing the likelihood chronic degenerative disease such as cancer, heart disease, stroke, and diabetes (and many more) is easier than you think once you know the secret. Although no supplement, diet, exercise, or lifestyle change can completely eliminate risk, The Vitamin D Solution will give you incredibly powerful, life-altering information that's as easy as getting some sensible sun exposure or popping a safe, inexpensive pill.
Michael Holick, the world's leading expert on vitamin D, is your guide on this journey of discovery. His pioneering efforts in that field go back to his days as a graduate student when he synthesized the active form of vitamin D, finding it to have extraordinarily powerful therapeutic effects. His contributions as both a scientist and practitioner have made profound advances in every aspect of vitamin D research. Dr. Holick has been a tireless researcher, advocate, author, educator, and legendary lecturer for over 30 years. He stands as the most prolific author of articles published in peer-reviewed medical journals including the prestigious New England Journal of Medicine.
I have a few predictions. The latter 2/3 of the 20th century will become known as the dark ages, when they demonized the sun, a situation that led to untold suffering and literally millions of largely preventable deaths. Dr. Holick will emerge as a central figure ushering in a new age where sunlight and vitamin D (along with other well-known lifestyle changes) eradicate millions of needless cases of chronic disease. Mainstream medicine will embrace the preventive and therapeutic power of vitamin D, and for his pivotal role bringing about the sea change in the practice of medicine, Dr. Holick will earn a well-deserved Nobel Prize. You heard it here first.
Dr. Holick contends that vitamin D deficiency is the most common medical condition in the world. Being both a researcher and clinician gives him tremendous insights to fortunate readers of this excellent reference. The book opens with two hypothetical pre-teen girls, one living in poverty near the equator and the other living a typical middle class American lifestyle. The list of diseases and medical conditions that are far more common for the middle class girl is shocking. It is no longer debatable that sunlight and vitamin D play major role in preventing a long list of serious chronic diseases, a reality that is becoming more and more accepted by the medical community.
Ideally you should read the entire book in linear fashion, but even if you open the book to random pages you'll find useful information everywhere, such as a new model of cancer that can't grow in a vitamin D-rich environment (page 87); the role of vitamin D in preventing Parkinson's and Alzheimer's (page 140); how vitamin D repairs pancreatic beta cells and thus is an important tool in the fight against diabetes (page 97); the only accurate way to test for vitamin D deficiency (page 147); and a new perspective on what killed the dinosaurs (page 28). I can't go over all 300 pages in this review but I hope you get the idea there is a lot of important information we all need to learn. The book is easy to read, devoid of oppressive jargon, easily accessible to the curious layman, covers the subject reasonably well, and would make an extremely good addition to the library of anyone who understands that good health comes from wise lifestyle choices. For these reasons, I am D-lighted to give the book a solid 5-star rating and the heartiest possible endorsement.
One of my favorite anecdotes involves a baby gorilla on the brink of death when Dr. Holick was called in to help. Classic symptoms of rickets led to an infusion of 5000 IU of vitamin D per day. The patient staged a remarkable recovery and Dr. Holick was the guest of honor at Kirmani's first birthday when she was clearly a happy, healthy, active gorilla. When Dr. Holick presented this story at a vitamin D conference in San Diego (complete with before and after photos) the audience burst into applause. I was there and can attest it was a magic moment. Read about it on page xxiv.
Another amazing story involves a lawyer who supplemented with vitamin D, developed symptoms of overdose, and called Holick to state he was planning to file a malpractice lawsuit. Dr. Holick had the lawyer send him the bottle of capsules which he thoroughly tested, only to find that due to a horrific manufacturing error the lawyer was actually taking over 1,000,000 IU a day. So instead of facing a grueling lawsuit, Dr. Holick acquired an important body of data since vitamin D overdoses are exceedingly rare. (Read about it on page 47.) The lawsuit was dropped, the lawyer quickly recovered, and we have valuable information about diagnosing and treating vitamin D overdose. Everyone wins.
Are there any negatives or downsides to this book? All my comments speak to the controversial nature of vitamin D where experts disagree in many areas. For instance, Holick states that D2 is equally as effective as D3 (page 217), yet the vast majority of researchers state that D3 is more bioavailable and stays in the system longer. On page 251 Holick states magnesium is unrelated to the uptake of vitamin D, which directly contradicts other experts. Holick generally avoids the details of studies that lead to various conclusions, which could be viewed either as a plus (easier to read) or a minus (lack of supporting evidence). There are more like this but I don't want to dwell on minutae. No two vitamin D experts see eye-to-eye on all aspects of this complex, confusing, confrontational subject. But this book contains so much solid, essential information it would be recommended reading for anyone even if they have minor disagreements here and there.
On page 214 Dr. Holick touches on a subject of utmost importance: Why can't the Institute of Medicine get it right when determining recommended vitamin D supplementation levels? The problem lies primarily in the guidelines of evidence-based medicine that only allows input from research reported in peer reviewed medical journals. Because pharmaceutical companies have no incentive to support research costing tens of millions of dollars to prove the value of an extremely inexpensive supplement, vitamin D studies tend to be of the lower-credibility observational type. Because medical science views this as a lack of compelling evidence the industry is hesitant to actively endorse vitamin D, and we all suffer as a result. I wish this flaw was exposed in a more forceful way but I'm glad at least was mentioned to give readers of this book some valuable insights. As a side note, The Institute for Functional Medicine promotes a system that sidesteps the flaws inherent in evidence-based medicine, and Dr. Mark Hyman, their most visible spokesman, provided a strongly supportive testimonial appearing on the back cover.
Here's the good news: You don't have to wait for the Institute of Medicine, the medical profession, or even your family doctor to jump onboard in order to benefit from the magic of vitamin D. However, you need to do your homework and that's where The Vitamin D Solution comes in. Dr. Michael Holick has done a superb job presenting information that will help you achieve optimal health. Read, it, study it, think about it, understand it, and most importantly, put it into action to get your 25(OH)D level above 50 ng/mL. (For most people that requires daily regimen of about 5000 IU.) The life you save may be your own.
It's no secret that despite all the modern technological advances in pharmaceutical medications and other disease treatments that are available out there on the market today, our society is still dealing with some of the most debilitating and devastating chronic health conditions we've ever seen in the history of the human race. This oxymoronic position has to leave people scratching their heads wondering what in the world is going on. How can we be so far ahead of the human race that existed just a half century ago and yet now we're falling so far behind that generation in terms of living a healthy lifestyle? There are a lot of theories about this floating around out there (including the notion that today's society is consuming far too much sugar and carbohydrates to be healthy), but Dr. Michael Holick thinks he's identified the common culprit that has made us fatter and sicker than ever before-Vitamin D! Yes, everybody and their momma is talking about Vitamin D these days and it's finally getting the recognition is deserves. But as the world's leading expert on Vitamin D studying it for over three decades, Dr. Holick has been on the cutting-edge of promoting the health improvements that people can experience by raising their Vitamin D3 levels for many years and now he's sharing all of his vast knowledge about it with us in his book The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problem.
Although it's referred to as a "vitamin," the reality is Vitamin D isn't a vitamin at all. It's actually a hormone that directly impacts so many areas of the body that it just makes sense to get your D3 levels up. Upwards of 200 million Americans are walking around with a severe Vitamin D deficiency and don't even know it. They've been told by well-meaning doctors that they have fibromyalgia, depression, genetic tendencies, and more. But if you check the D3 blood work, I would venture to guess that nine times out of 10 their Vitamin D levels are probably on the low to extremely low end of the spectrum. My own wife Christine dealt with this a few years back when she was experiencing excruciating joint and muscle pain as well as fits of depression and panic attacks only to find out here D3 came in at a dismal 9 ng/mL! If you don't know what that means, let's just say it's not good at all. She began taking 10,000IU D3 gel caps for a year and was able to raise her levels to 52 ng/mL. Now she has no more joint and muscle pain and she came off of a 10-year reliance on Paxil to control panic attacks. That's the miracle of Vitamin D and the stuff is dirt cheap, too! Yes, knowing your Vitamin D levels is a big deal.
So how in the world did we suddenly become so Vitamin D deficient? Lack of sunlight exposure, poor nutrition, and inadequate or severely lacking sources of it in supplements and fortified foods (like milk) are most of the problem. But regardless of how we there, the good news is there is a solution just waiting for those people who are dealing with any number of health ailments that cannot be explained by modern medicine or the symptoms are simply being masked by risky drug therapies. What is it? GET MORE VITAMIN D! How do you do that? Well, it depends on where you live, but sun exposure may not be enough if you live north of Atlanta or San Diego and you can't get enough of it in the foods you consume either (it would take 50 egg yolks to get adequate amounts of Vitamin D-talk about an eggfest!).
Dr. Holick says he prefers you get your Vitamin D from the sun first and foremost and to only use supplementation as an added aide to get your levels increased to where it needs to be. What level do you want your 25-vitamin D level to be? Ideally between 30-100 ng/mL according to Dr. Holick with the sweet spot landing in the middle around 60-80 ng/mL. Below 20 ng/mL is considered deficient while below 30 ng/mL is insufficient. Again, upwards of two-thirds of the American population is Vitamin D deficient right now. This is directly impacting health to the extent that ailments like osteoporosis, heart disease, cancer, autoimmune diseases, insomnia, arthritis, diabetes, chronic pain, psoriasis, autism and so much are likely a direct result of these deficiencies in something you can buy a big bottle of for around $10 at Sam's Club along with adequate sunlight exposure.
In The Vitamin D Solution, Dr. Holick includes a "self-test" in Chapter 7 to see what level of deficiency you may be experiencing. Things like sun exposure, where you live, what vitamins you consume, what kind of foods you eat, what beverages you drink, your nationality and race, your age, whether you are overweight or obese, your pain tolerance, your energy and strength, medications you are taking, and specific diseases you are dealing with will help you know even before having a Vitamin D blood test conducted whether you have a susceptibility to being deficient. Of course, the best thing you can (and should) do is get tested. What you need to have run by your doctor is the 25-hydroxyvitamin D test, aka the 25(OH) D test. It will show you how much circulating Vitamin D you have in your body. Beware of doctors ordering the wrong test and thinking your Vitamin D levels are fine. And don't get fooled into filling that useless prescription for a once-a-week 50,000IU Vitamin D2 pill that costs an arm and a leg (although Dr. Holick believes it will help "fill an empty Vitamin D tank!"). What you want is D3 which is very affordable from virtually any drugstore, pharmacy, or Wal-mart in varying doses as low as 100IU capsules to 5000IU gel caps. Get tested and respond accordingly!
The good news Dr. Holick brings with this book is that there is a real "solution" to your Vitamin D deficiency that is as easy as setting aside time for deliberate sun exposure, making sure you are consuming adequate amounts of calcium in your diet so that the Vitamin D can be maximized for health, and making up the difference in your Vitamin D needs through supplementation. And lest anyone, medical professionals especially, warns you of Vitamin D toxicity, Dr. Holick is quick to note that your body cannot manufacture a toxic level of Vitamin D from simple sun exposure no matter how much sun you get. And supplementation isn't a problem unless you are taking super-high doses well above 10,000IU for longer than six months. The bottom line is to make sure you are taking every measure possible to increase your D3 levels to ward off any potential negative effects on your health.
The Vitamin D Solution is arguably the most comprehensive book on the subject of Vitamin D today and Dr. Holick certainly knows from whence he speaks. He's been trumpeting the case for Vitamin D awareness for a very long time and is just now receiving the critical acclaim he rightly deserves. My favorite part of this book is in Chapter 13 which is the "Q&A" session that answers anything and everything you can possibly think of regarding the subject of Vitamin D. He also provides a resource guide for finding good sources of Vitamin D supplementation as well as a bibliography of other Vitamin D experts and researchers he cites in support of the conclusions he draws throughout his book. Needless to say, I'm a big fan of Vitamin D and the positive effects it can have on your health. My own Vitamin D levels increased from 42 ng/dL to 68 ng/dL taking 10,000IU D3 gel caps in just six months, so it is indeed possible to overcome many chronic health problems with a concerted effort to make it happen naturally. Isn't it time to stop suffering needlessly from Vitamin D deficiency?
on April 3, 2010
After reading 7 books and over 2,000 articles on vitamin D during the past 4 months I still had many notes to take when reading this excellent book. Sometime I took the notes were because Dr. Holick presented the information in a way that I could finally understand, and in other cases the information was new to me. Three pages of my notes are at VitaminDWiki dot com. The Power of Vitamin D probably provides a better first book on this subject.
As intrigued as I am by the premise of the book, I approached it with some skepticism - but my reservations were quickly put to rest. The book is easy to understand and the information presented in a logical manner. Rather than the material appearing to be on the fringes of traditional medicine, Dr. Holick details in the first seven chapters of his book, the research and reasoning behind his premise.
The subject matter may sound like dry reading, but it was written in a very readable way and I finished it in a couple of days. I am not well versed in medical terminology yet I had no problems reading or understanding anything in the book - all was adequately explained. There is a comprehensive index which makes finding areas of particular concern quick and easy. A resource guide aids in finding particular products mentioned in the book - like a Vitamin D producing light. A selected bibliography lists eighteen pages of research studies. The author notes that if he included all relevant Vitamin D research studies it would have filled thousands of pages. And, one of my favorite sections of the book is a Q & A section where common, and some uncommon questions regarding Vitamin D deficiency are addressed. An example of a question contained in the section is -- "If you fry fish in oil, does that remove Vitamin D? The answer is yes - more than half is lost and the fish should be baked, broiled or grilled instead.
Other reviews have detailed specific, sometimes surprising information regarding Vitamin D deficiency, why most of us have this deficiency, along with why the medical community has misidentified the optimal levels that should be maintained, so I won't reiterate that information here. But, this information provides the explanation as to why our basic multi-vitamin supplements and milk fortification simply isn't sufficient.
What I found of concern is that after reading the compelling arguments made by Dr. Holick as to why a host of ills may be caused by a Vitamin D deficiency, ills that may be easily resolved once the deficiency is identified, the ability to obtain this vital test may not be so easy to obtain.
Dr. Holick explains why simply requesting the test may not prompt your doctor to approach the insurance company for authorization. The test isn't one normally run during a routine physical. The problem, as is usually the case, is about money. The test isn't cheap and some insurance companies discourage doctors from requesting it. Dr. Holick feels this test is important enough for all of us to determine our Vitamin D levels, that he actually suggests changing doctors if your doctor won't recommend the test.
To be able to potentially correct a number of serious health issues, inexpensively, by simply correcting a Vitamin D deficiency is surely worth exploring. I would encourage everyone to read the book and decide for themselves.
on November 2, 2010
Dr Michael Holick is arguably the preeminent vitamin D researcher for over the past 30 years. A search of the ISI Citation Index for "M.F. Holick and Vitamin D" shows 389 peer-reviewed scientific papers that he has authored or co-authored. These papers have been cited by other researchers an incredible 13,000 times, which indicates his huge contribution to the field of vitamin D research.
The Vitamin D Solution is a synopsis of the current state-of-the-art in vitamin D research. The impact of vitamin D on health is profound and goes way beyond absorption of calcium (although that is important). There are vitamin D receptors in every single cell in the body, with far-reaching effects on a whole host of cellular processes within the body.
It's a good news/bad news/good news story. The good news is that vitamin D can prevent and treat a host of diseases including heart disease, cancer, type 1 and 2 diabetes, tooth decay, multiple sclerosis, obesity, depression and dementia, amongst others. The bad news is that we are overwhelmingly deficient in vitamin D. This includes the majority of young women and their babies, with enormous implications for childhood development and health. Vitamin D deficiency is so widespread that Dr Holick uses the alarming term "pandemic". The good news is that vitamin D deficiency can be alleviated through sensible sun exposure and/or inexpensive supplements.
In case you are unaware, vitamin D, which is actually and hormone and not strictly a vitamin, is produced naturally by the skin through exposure to sunlight (specifically the tanning UVB rays). Vitamin D can also be obtained through diet, although this amount is very small in a typical North American diet. Vitamin D supplements and sensible sun exposure are recommended. Dr Holick describes the various provitamin, circulating and active forms.
The current recommended daily intake of vitamin D of 400IU is described as woefully inadequate. Dr Holick recommends that, in addition to sensible sun exposure, children and adults supplement with 1000-2000IU of vitamin D per day to maintain optimal blood levels. Pregnant women and obese individuals require considerably more. He considers that the "upper tolerable level" of vitamin D that can be consumed with absolute safety is upwards of 10,000IU per day.
Dr Holick takes square aim at the anti-sun zealots especially his dermatology colleagues. In fact, in 2004 he was forced to resign from his position as Professor of Dematology at Boston University School of Medicine for recommending modest and sensible sun exposure, and condoning the responsible use of tanning beds.
The Vitamin D Solution is divided into 2 parts. The Part I covers the science and history of vitamin D research and its role in disease and in animal and human evolution. This includes a checklist to determine whether you are a candidate for vitamin D deficiency, and the appropriate blood test for the major circulating form of vitamin D (the test is referred to as serum 25(OH)D test). Optimal ranges for the serum vitamin D levels are 40-60 ng/ml, and deficient is defined as less than 20 ng/ml.
Part II describes three steps to maintaining or rebuilding your vitamin D levels, which are (1) sensible sun exposure, (2) adequate calcium intake along with good dietary sources of vitamin D, and (3) vitamin D supplementation. Dr Holick refers to vitamin D and calcium as the dynamic duo (research from Europe and Japan would also include vitamin K2 as the terrific trio).
There is also an excellent and very informative Q&A section.
My own personal grumble is that there is no mention of Sir Edward Mellanby or his wife Lady May Mellanby and their groundbreaking research in Britain during the 1920's and 30's, which included the discovery of vitamin D in cod liver oil, dietary cure for the childhood bone disease rickets, and Lady Mellanby's use of vitamin D to treat tooth decay. The discovery of vitamin D, the role of sunlight, dietary sources and its treatment for rickets is a first-rate and fascinating detective story that is not covered very well here.
I give The Vitamin D Solution 4 out of 5 stars. It is certainly required reading for those of us who are interested in health and nutrition and taking responsibility for our family's health. It provides a clear prescription for how to get tested for vitamin D levels, and what to do to rebuild and maintain optimal levels. This book would appeal to the more science-oriented reader. Others may find it a little overwhelming. There is a vast bibliography for those of us who like to check the original references.
If you prefer not to wade through the science, you might do with a very user-friendly summary and review in November's Oprah magazine.
on October 16, 2011
I have my masters in toxicology and public health. I agree that the book does not site references, nor have an index of them (studies), but since the author was mostly speaking about his own studies, I gave him a pass. He does have a bibliography in the back, but I can't see where it's linked to his statements. Dr. Holick does state facts implying causation without robust data. I'm thinking because he's one of the foremost researchers on the subject, he didn't write this book for peer review, but just to get the info. to the masses. I like his theories and like to "try them out" for myself.
When you're in pain, you'll try anything. This time, wow!!! I've been struggling with fibromyalgia for 12 years and found myself feeling better after only a week of vit. D supplements. The doctor recalls an incident where one of his readers began D supplementation but the pharma company miscalculated the dose in the supplement. This poor man became toxic off vit. D. Anyone wanting to supplement with vit. D or read up about what it's used for and where it's used in our bodies, will love this book and his personal stories are educational.
Hey...if I held part of the cure to some forms of cancer and diabetes and didn't write about it...I'd be a pretty horrible person. I give this doctor two thumbs up for his book and I'd ask him to re-edit the next printing and add some citations for each study he references so we can look them up. I wish every high school health/science class taught this stuff.
on April 19, 2010
This book is without a doubt and eye opening learning experience about the power of Vitamin D, and the harmful effects on our body when we are deficient in Vitamin D. I couldn't put this book down. I already take 2000 I.U. of D per day as prescribed by my Dr.
As of this reading, I have now incorporated more time outside in the sun, as natural D from sunlight lasts far longer in the body than supplements alone.
Great book, you won't be disappointed. Very enlightening.
on May 10, 2010
If The Vitamin D Solution gets the attention it deserves, it could have a greater benefit for public health than all the drugs on the market today, except perhaps antibiotics. In this book, Dr. Holick presents overwhelming scientific evidence that vitamin D plays a crucial role in the body's immune system, mood, brain and heart health, and weight and strength. He also shows that vitamin D deficiency is epidemic in the northern hemisphere and is a central player in the prevalence of conditions like diabetes, cancer, stroke, fibromyalgia, osteoporosis, depression and many more.
Dr. Holick's scientific credentials are impeccable, and even the mass media are beginning to climb on the bandwagon and talk about vitamin D supplements. Sunshine is free, but a combination of lifestyle and scare tactics about skin cancer has made us shun its life-giving benefits. One of the most sobering statistics in this very readable book is that for every one person who might die because of skin cancer due to over exposure to the sun, 55 people will die due to lack of vitamin D - the sunshine vitamin made by our skin.
He gives detailed recommendations about vitamin D supplementation as well as for how to strike an optimal balance for sun exposure with minimal risk. The book is full of fascinating case studies and research reports that delight a medical nerd like me. One of the most fascinating to my mind was the role of vitamin D in ensuring communication among cells. One of the characteristics of cancer is the breakdown of this communication, allowing cells to go rogue. Sounds like a metaphor for society...
I really think that everyone who works indoors all day needs to read this major wake-up call.
on October 27, 2013
This book would be excellent if it simply had a few sentences of summary for each chapter. What I mean is this: Yes, have the long-winded explanation but also include a short summary of what each chapter says at the beginning or end of each chapter.
Dr. Holick has been researching Vitamin D (or should I say Hormone D) for decades and is eminently qualified to preach on this topic. But most of us would rather start with the short story (cut to the chase) and have the details available if we wish to get more in-depth.
Also, I don't remember Dr. Holick acknowledging that supplementation might be different than getting your vitamin D through the sun. There is a very big and important NIH study going on right now that looks at vitamin D supplementation. That study will finish in 2014, but the results will be not be available until a few years after the completion of the study. It is possible that study could show us some negatives in regard to vitamin D supplementation. There have been a few minor chinks in the armor of vitamin D supplementation that Dr. Holick does not discuss. That is perhaps OK since these things have been quite minor and not well documented, but I still think a tiny bit of caution is warranted. Boy, I'm not saying this well at all! Maybe I need to be more long-winded :)
I currently believe in getting a fair amount of vitamin D and trying to get it from sunshine when possible. If not possible, get it from supplements. But there are some things we don't know about vitamin D and a lot of what Dr. Holick says is subject to possible change in the next few years. Keep your ears and eyes open.
All in all, a much needed book that properly strikes at the medical leviathan and exposes another area of misguided and harmful dogmatism (counseling against all direct sunlight). The book would be 4 and 3/4 stars if it had a summary paragraph for each chapter.