Friday Q&A: Back and Inversions for Chair Yoga

This week, we have a follow-up question to our Friday Q&A on chair yoga (see Friday Q&A: Chair Yoga) from one of our readers who actually teaches a chair yoga class

Q: I teach a chair yoga class which cannot go to the floor for healthy aging. How can I do a safe inversion or back stretch that does not stress the osteopenic back?

A: If you teach chair yoga, many students are older or infirm and not able to transfer from standing or sitting in a chair to the floor, where you might have them do any number of reclining poses that could stretch the back or approach an inversion, like Legs Up the Wall pose (Viparita Karani). 

If by “back stretch” you mean a forward bending action of the spine, like in Standing Forward Bend (Uttanasana), in light of possible osteopenic or osteoporotic spine, you need to be careful with most forward folding positions (see What is Ostepenia and How Can Yoga Help?).  It is not hard to do a seated version, however, if that is what you are looking for. One of my favorites that is fairly shallow and would not create too much force on the vertebrae of the spine would involve placing a second chair in front of the first, facing it away from you. Then ask your students to tip as much as possible from the hips and place their crossed forearms on the top seat back of the chair in front of them. This is similar to seated forward fold we showed for our Office Yoga series (see Featured Pose: Chair Forward Bend).

If, however, by “back stretch” you are referring to a back-bending action, then there is a bit less concern of hurting the spines of students with OP.  In seated Cat/Cow pose, the Cow variation is a nice, easy backbend shape that most could do in the chair. (See Featured Pose: Chair Cat Pose.)

Or, have the students stand behind the chair, use the top back rung for their hands for balance purposes and do a gentle standing backbend from Mountain pose (Tadasana).

As for inversions, this may be a bit tougher. You could have them put their chairs against the wall, and if they still have good hip mobility of rolling the pelvis over the femur bones, you could do a Downward-Facing Dog version with the hands on the seat of the chair, walking the hips and feet back into this higher version of regular Downward-Facing Dog, but with a slight downward slant from hips to hands. Make sure they bend their knees as they walk forward towards the chair at the end of the pose, and rise up slowly monitoring for any lightheadedness or dizziness. (See Featured Pose: Downward-Facing Dog (Chair Version)).

And you could show the class how to do Legs Up the Wall pose on the ground, demonstrating it for them, and suggesting they try this at home in their beds, swinging the legs up the headboard side of the bed if the bed is up against a wall. I’d have them only stay for 2 minutes or so at first, as you will not be there to monitor them. Of course give them all the usual precautions regarding inversions and high blood pressure and glaucoma, as the older your crowd, these conditions are more common. I hope these suggestions give you things to consider. And armed with the information from our posts on OP, you can be creative in your approach to working with your chair yoga classes.

—Baxter

What is Osteopenia? And How Can Yoga Help?

by Shari

Last Friday Baxter answered a reader’s question about osteopenia (see Friday Q&A: Yoga and Osteopenia), regarding whether or not yoga practice on its own is sufficient to maintain and/or increase bone strength. By chance, we recently received a request for an article addressing “dangerous” poses for osteopenia. Since most of you probably don’t know much about osteopenia—and its relationship to osteoporosis— we decided it was about time to provide some background information about the condition. I promise I’ll get around to answering the reader’s question eventually! Look for it this coming Friday.

Let’s start by discussing osteoporosis, which is a disease in which bones become fragile and are more likely to break or fracture due to loss of density (not bone strength). It is not painful and many people (both men and women) don’t even know they have it or are at risk for developing it until they take a DEXA scan. The DEXA scan (dual energy X-ray absorptiometry scan) measures bone mineral mass, because medical researchers have discovered that there is a correlation between bone breaking and bone density loss. But the DEXA scan can also cause lot of confusion because it doesn’t take into consideration the different way bones are constructed. Some bones are short and fat, and some are long and thin, and differently shaped bones can have different density readings. Bone mass is affected by both how densely a bone is constructed and by its corresponding physical dimensions.

Femur Bone

The World Health Organization has defined the statistical measurements of bone density through a system of comparing your numbers to women of the same age, height and weight, and then comparing them to the average measurements of women age 25-30 that are at the peak of bone strength. Three areas are measured in the DEXA scan: lumbar spine, total hip, and surgical neck of the femur (thigh bone). Two scores are given:

• T score, which is the measurement of bone mineral density and how your score compares to healthy 25-30 year old women.
• Z score, which is the comparison to women your age, height and weight.

Osteopenia is defined as a T score of 1 to 2.5 standard deviations below the mean (negative numbers), and means that you are at risk for developing osteoporosis. Osteoporosis is defined as a T score of 2.5 standard deviations below the mean (negative numbers). The higher the T score (or the more negative the numbers), the higher the fracture risk.

The correlation between a low bone mineral-density reading in a DEXA scan and a higher fracture risk is stronger than the relationship between high blood pressure and a stroke. But even though the test detects 9 out of 10 people with osteoporosis, the test is not perfect and it wrongly diagnoses healthy bones between 5-7% of the time. Also, readings will differ in different test sites, so for consistency the same test facility needs to be used for repeated scans.

So how does yoga fit into this picture? Bone has two main components: outer bone and inner bone. Bone is a living matrix of living cells and canals that are interrelated. Outer bone, which surrounds inner bone, is called the cortex and it forms a hard outer ring and is a large part of bone strength. Its construction is fairly uniform in individuals. Inner bone is spongy and is called cancellus or trabecular bone. It varies greatly in individuals. For us to improve our bone health we want to not only build outer bone but also inner bone.

Wolff’s law describes bone strength as follows:

1. The architectural strength of a bone develops along the lines of force that the bone is subjected to.
2. If a bone is loaded, the bone will remodel itself over time to become stronger and resist that sort of loading.

In conjunction with Wolff’s law there are some other important forces that act on the bones to improve bone strength and density:

1. Gravity increases bone loading. 
2. Muscle contraction increases bone loading. Dynamic tension occurring between muscle agonist and antagonist affects the bones by applying opposite pressures, and the forces are doubled on the bone.
3. Muscle activity stimulates bones to strengthen themselves more vigorously than weight bearing alone.

In our yoga asana practice, we not only take weight-bearing positions, such as standing poses, but all the active poses involve muscle contraction in some form. And the great variety of poses and movements means that all your bones are involved! In addition, Dr. Loren Fishman cites from his extensive research on osteoporosis that bone stimulation (growth) occurs after 12 seconds of static (isometric) hold but not more after 72 seconds of hold. 20-30 second holds are recommended for bone stimulation. And 20-30 second holds are quite typical for many of the poses we practice.

Now you can see why yoga is recommended for people with osteopenia as a way to prevent the development of osteoporosis and is also considered beneficial for people who already have osteoporosis. And for those of us who don’t have either condition, yoga is a very versatile and adaptable way for maintaining our bone strength. However, because osteopenia means more fragile bones, certain yoga poses are considered risky for people with the condition. Tune in Friday for my answer to the reader’s question about those poses.

Osteoporosis, Balance and Yoga

by Brad

A couple weeks ago, I attended a very interesting seminar on “Bone Marrow Adiposity:  An Age-Associated Phenotype; What's between bone and fat?  New insights into age-related osteoporosis” by Dr. Clifford Rosen, MD.  Dr. Rosen is the Director of the Center for Clinical and Translational Research at the Maine Medical Center Research Institute in Scarborough.  His talk was fairly technical and had to do with the regulation of fat in bone and how it increases slowly with age, as well as being affected by other environmental and genetic factors. His data showed that as fat accumulates in bone with age, it appeared to be related to a decrease in bone density, and therefore could be a driver of osteoporosis in both men and woman. He also stated that the clinical manifestation of osteoporosis is bone breakage, and therefore as your bone density decreases, it is the fall and inevitable bone fracture that typically turns people into patients. Avoiding a fall in the first place is possibly the best and for some the only way to avoid the adverse effects of this age-related decline in bone density.

After his seminar, I had a chance to talk with him after his research and asked him whether yoga might help by decreasing the risk of falling. He immediately said yes, and added that the yoga and tai chi were the two things that he knew that had been shown to have the greatest benefits in reducing this falling and bone fractures (see, for example, the Mayo Clinic web site's Exercising with osteoporosis: Stay active the safe way by choosing the right form of exercise and the New York Times article Ancient Moves for Orthopedic Problems). He implied that this was primarily through an increase in balance as opposed to strength. Indeed, while there is plenty of evidence that strength training is important, an increase in balance and flexibility can make all the difference between a stumble or misstep and a full-fledged fall.

As I sit on my flight to Seattle, I am reminded of how much variation exists in flexibility and balance among adults. Squeezing out of an aisle seat to make your way to the restroom or retrieving a suitcase from the overhead bin can easily become an awkward and precarious—and at times dangerous—act. And it is often not the oldest passengers, but the middle-aged and muscle-bound adults who induce serious cringing from neighboring passengers. Imagine how much more agile they would be if they all practiced yoga!

And for those of us who already do yoga, this is yet another compelling argument that working on balance is critical as we age. So if you haven't done so already, check out Shari's post last week about how to create a yoga practice to improve your balance (see Planning a Practice for Improving Balance).

Friday Q&A: Is Loren Fishman's Osteoporosis Sequence Safe?

Q: You say that people should not do the same poses all the time. What about programs like Dr. Fishman's osteoporosis study, which has participants doing the same sequence of poses every single day?

A: Thanks for this question. Indeed, if a person does the same sequence day in and day out, you could run the risk of a repetitive strain injury. The fact that Dr. Fishman's sequence is only supposed to take 10 minutes a day to do means that the practitioners are not holding the poses terribly long, which would reduce this risk considerably. However, a review of the poses taught (see here) reveals several poses that I feel could be potentially injurious to the wrists, neck and lower back, these being Upward Bow pose and the deep seated forward bends. I would consider other poses if I were to design such a practice, but Dr. Fishman does mention tailoring the sequence to students individual needs. I would suspect that this had to be done quite a bit.

Recall that the number of patients that started the study was much larger than those that completed the study. (117 vs 11). Interestingly, there is no discussion as to what caused so many to drop out  and why they were unable to do a 10 minute practice everyday. One factor could have been boredom, which is why I often suggest that students alternate practices from day to day to help maintain better focus and follow through. And it is possible that some found the sequence too advanced, despite the individual adjustments offered. The bottom line, in real life, when you can vary your practice, I highly recommend you do so.

—Baxter

A: With Baxter's blessing I'm going to tell you why I wouldn't want to do this sequence on a daily basis. I'll start by telling you that the three yoga injuries I've sustained have all been repetitive strain injuries. I was a pretty enthusiastic practitioner for a number of years, and did a lot of standing poses and sun salutations. And the injuries I had were: sacroiliac joint injury (common among dancers and yoga practitioners, but not the general public), tennis elbow (possibly from sun salutations), and housemaid's knee (from kneeling too much on the bare floor).

Now let's look at the sequence:

1. Triangle Pose (Trikonasana)
2. Downward-Facing Dog Pose (Adho Mukha Svanasana)
3. Upward-Facing Dog Pose (Urdva Mukha Svanasana)
4. Bridge Pose (Setu Bandhasana)
5. Upward Bow Pose/Rainbow Pose (Urdva Dhanurasana), without or with a chair
6. One-Legged Forward Bend (Janu Sirsasana)
7. Two-Legged Forward Bend (Paschimottansana)
8. Boat Pose (Navasana)
9. Reclined Leg Stretch (Supta Padangusthasana)
10. Marichyasana 1 twist
11. Lord of Fishes twist (Matsyendrasana)
12. Reclined Twist (Jathara Parivarthasana)

After I got over the shock of trying to imagine doing all those poses in 10 minutes, without any warm-ups, I examined the poses in detail. First, two of the poses in the sequence are known for causing sacroiliac joint injuries, Triangle pose (Trikonasana) and One-Legged Forward Bend (Janu Sirsasana), with One-Legged Forward Bend a particularly guilty party. For me, personally, I've concluded it's just not good to do either of those poses every single day. Then, as Baxter mentioned, there is a very deep backbend in the sequence, Upward Bow, and doing this every day could put a lot of strain on the wrists and elbows, but of just as much concern to me is that it is followed immediately by a deep forward bend, taking the lower back into such extreme movements with no rest between. In particular, the Two-Legged Forward Bend is known for causing lower back strain. The combination of the deep backbend followed by the deep forward bend could cause a lot of back strain (personally, I would have moved the forward bends to the end of the sequence). The sequence ends with three twists, asymmetrical poses that are also hard on the sacroiliac joint, with no symmetrical counter pose to finish the sequence. (On the bright side, no danger of housemaid's knee here.)

I understand some of the thinking behind this sequence, which tries to engage all the different muscles of the body to strengthen as many bones as possible, within a short sequence, and uses the twists to "release" the back after the strain of the backbends and forward bends. However, if I were to design an osteoporosis practice, for safety's sake, I would develop five or more different sequences that the practitioner could alternate between on different days, rather than trying to cram everything into one single practice. There are so many wonderful poses in the yoga tradition, why would you limit yourself to just 12?

—Nina

FEATURED POSE: WARRIOR 2

by Baxter and Nina

This week’s featured pose is one of Baxter’s favorite poses for osteoporosis (see here). In addition to building bone strength, Warrior 2 strengthens your arm and leg muscles. This pose also improves your balance and stretches your inner thighs. The variations we describe below make it accessible to almost everyone (it can even be done on a chair).

Baxter prescribes Warrior 2 for:

• osteoporosis
• balance problems
• anxiety (it burns off excess energy and is “grounding”)

Warrior 2 Pose (from Moving Toward Balance)

General Instructions:Step your feet wide apart (about the length of your legs). Turn your right foot out about 90 degrees and your left foot in slightly, so the toes of your back foot line up with the long edge of your yoga mat. Inhale and extend your arms out to your sides. Then exhale and bend your right knee toward 90 degrees (but not further), making sure your right knee is aligned with your middle right toe. If it’s comfortable for you, turn your head to gaze over your right hand. Repeat the pose on your left side.

Recommended Timing:30 seconds (8 breaths) for beginners, working up to 1 minute (12 to 16 breaths)

Some helpful variations:

1. To build arm strength, leave your arms up while changing from the right side to the left.

2. If you have balance problems, practice with your back to a wall, with the hip of your front leg touching the wall. If balance is a serious concern, you can touch your hands to the wall as you bend your knee and while you stay in the pose.

3. If you are generally weak or tight in the hips, practice the pose with your back heel touching the wall. This is also useful to get a clear sense of the straightness of your back leg.

Cautions: If you have knee problems, don’t bend your front knee quite as deeply. Make sure it stops just shy of being over the front ankle. In addition, standing with your feet a bit closer than the 4 to 4 1/2 feet apart that is usually recommended can also help. And if your knee is acutely painful, you could sit on a chair with your front thigh supported by the chair seat to take all weight off your front knee.

Warrior 2, with feet closer, knee less bent (from Moving Toward Balance)

POSES FOR OSTEOPOROSIS

by Baxter

As promised, today’s post will address a few of my recommendations for yoga for osteoporosis. As many of you know, OP is a very common condition that increases in incidence as we age. And before you fellas tune this out with the common misconception that OP is just a woman’s condition, it might surprise you to learn the following statistic from the Mayo Clinic: 1 in 8 men over the age of 50 will suffer an osteopenic fracture! And what are the most common fractures in men and women? The hips, spine and wrists are the areas most commonly affected.

The easiest lifestyle recommendation to have a positive impact on the progression of the condition is weight-bearing exercise. And although there are other forms of physical activity and exercise that fall in that category, all of yoga’s poses or asana fit the bill, and unlike walking, yoga actually requires that we bear weight on not just the feet, but the wrists and the spine as well, so in my estimation yoga is far superior to walking alone.

Three classic modern poses that are well known to most yogis are good examples of poses that are good for OP:

Warrior 2: I like this one because you are balancing on both feet, which is easier than on one foot, yet it is still a challenge for your balance receptors. And not only are you bearing weight, but if you do the pose for 1-2 minutes, you notice that you are also building strength and endurance in your legs and arms. (Later this week, we’ll talk about this Warrior 2 in detail. See here.)

Warrior 2 Pose from Moving Toward Balance

Downward-Facing Dog: Since all four of your limbs are in contact with the floor, balance is not much of an issue, but you are now bearing weight on your hands, wrists and arms as well as your legs. This will stimulate the bones of the upper extremities and could lead to increase density in these areas.

Downward-Facing Dog Pose from Moving Toward Balance

Tree Pose: For immediately obvious reasons, Tree pose will challenge your ability to remain balanced on one leg. The supporting leg must really work and be strong and stable to keep you upright, and the other leg’s hip gets a bit of opening from its position. And although this or any yoga pose will not eliminate the chance of a fall at some time in your future, more than one of my students has reported that after taking an unexpected spill, they felt their yoga practice prepared them to fall more gracefully and minimize the injury they sustained.

Tree Pose from Moving Toward Balance

Keep in mind that if you are young and/or without evidence of OP at this time, a regular practice could be preventative. If you have been diagnosed with osteopenia, the precursor to OP, it is possible that your regular practice could stabilize or even reverse the trend of thinning of the bones, at least according to a recent pilot study by Loren Fishman, MD. The same is true if you already have OP, but have not suffered fracture; but you will need to be a bit more cautious as you practice, and I’d recommend that you take class with an experienced teacher familiar with modifying the poses to fit your individual needs.

Even 10 minutes a day may be enough yoga asana to impact OP, so why not start today with these 3 poses?

ACTIVE ENAGAGEMENT: YOGA AND OSTEOPOROSIS

by Baxter

Earlier this summer, some good news was reported in the New York Times about recent study on the benefits of yoga asana for osteoporosis. Physiatrist Loren Fishman, MD (a physiatrist is an MD who works mostly with helping to rehabilitate those with chronic illnesses and injuries without the use of surgery) released the results of a study on the potential benefits of yoga on the progression, or course, of osteoporosis. Originally enlisting over 180 subjects, the study had participants attend a series of classes to learn a short 10-minute home yoga practice that they were then asked to do daily for two years. Knowing human nature, it is perhaps not surprising that only 11 participants were able to complete the study as required. But those who did had some very encouraging results: an increase in the bone density of hips and spine, while the seven controls with osteoporosis continued to lose bone mass. That’s right, the bones of the yoga practitioners actually got stronger. The downside to this result, of course, is the small number of folks who stuck to it, which means that additional larger studies will be required to confirm these initial encouraging results.

Roots and Water by Brad Gibson

 Sadly, we live in a culture that often is looking for the quick fix, the one-pill solution, or the single visit to the doc for the cure. The yoga tradition is pretty clear on how positive change occurs, and how goals are met through regular practice done over the long haul. And this ongoing active engagement concept seems supported by the results from this study. Got 10 minutes a day?

For more about this study and what it might mean for you, check out the New York Times article here. You can get complete information on the study (and see the poses included in the osteoporosis yoga practice) here.

Next week, my Rx for osteoporosis in your home practice. If you can’t wait till then, know that all of your yoga poses are “weight bearing,” so keep on doing some poses you love for now, and I will add in my favorite picks next time!

And remember to ask us questions for our Friday Q&A. Leave questions in a comment or email us at the address under "Contact Us" to the right. 

Maybe you should stop trying to be someone you are not

Many people struggle to lose body fat, and never quite make it to their optimal. Fewer people manage to do so successfully, and, as soon as they do, they want more. It is human nature. Often they will start trying to become someone they are not, or cannot be. That may lead to a lot of stress and frustration, and also health problems.

Some women have an idealized look in mind, and keep losing weight well beyond their ideal, down to anorexic levels. That leads to a number of health problems. For example, hormones approach starvation levels, causing fatigue and mood swings; susceptibility to infectious diseases increases significantly; and the low weight leads to osteopenia, which is a precursor to osteoporosis.

In men, often what happens is the opposite. Guys who are successful getting body fat to healthy levels next want to become very muscular, and fast. They have an idealized look in mind, and think they know how much they should weigh to get there. Sometimes they want to keep losing body fat and gaining muscle at the same time.

I frequently see men who already look very healthy, but who think that they should weigh more than they do. Since muscle gain is typically very slow, they start eating more and simply gain body fat. The reality is that people have different body frames, and their muscles are built slightly differently; these are things that influence body weight.

There are many other things that also influence body weight, such as the length of arms and legs, bone density, organ mass, as well as the amount of glycogen and water stored throughout the body. As a result, you can weigh a lot less than you think you should weigh, and look very good. The photo below (from MMAjunkie.com) is of Donald Cerrone, weighing in at 145 lbs. He is 6 ft (183 cm) tall.

Mr. Cerrone is a professional mixed martial arts (MMA) fighter from Texas; one of the best in professional MMA at the moment. Yes, he is a bit dehydrated on the photo above. But also keep in mind that his bone density is probably well above that of the average person, like that of most MMA fighters, which pushes his weight up.

A man can be 6 ft tall, weigh 145 lbs, and be very healthy and look very good. That may well be his ideal weight. A woman may be 5’5”, weigh 145 lbs, and also be very healthy and look very good. Figuring out the optimal is not easy, but trying to be someone you are not will probably be a losing battle.

Low bone mineral content in older Eskimos: Meat-eating or shrinking?

Mazess & Mather (1974) is probably the most widely cited article summarizing evidence that bone mineral content in older North Alaskan Eskimos was lower (10 to 15 percent) than that of United States whites. Their finding has been widely attributed to the diet of the Eskimos, which is very high in animal protein. Here is what they say:

“The sample consisted of 217 children, 89 adults, and 107 elderly (over 50 years). Eskimo children had a lower bone mineral content than United States whites by 5 to 10% but this was consistent with their smaller body and bone size. Young Eskimo adults (20 to 39 years) of both sexes were similar to whites, but after age 40 the Eskimos of both sexes had a deficit of from 10 to 15% relative to white standards.”

Note that their findings refer strictly to Eskimos older than 40, not Eskimo children or even young adults. If a diet very high in animal protein were to cause significant bone loss, one would expect that diet to cause significant bone loss in children and young adults as well. Not only in those older than 40.

So what may be the actual reason behind this reduced bone mineral content in older Eskimos?

Let me make a small digression here. If you want to meet quite a few anthropologists who are conducting, or have conducted, field research with isolated or semi-isolated hunter-gatherers, you should consider attending the annual Human Behavior and Evolution Society (HBES) conference. I have attended this conference in the past, several times, as a presenter. That gave me the opportunity to listen to some very interesting presentations and poster sessions, and talk with many anthropologists.

Often anthropologists will tell you that, as hunter-gatherers age, they sort of “shrink”. They lose lean body mass, frequently to the point of becoming quite frail in as early as their 60s and 70s. They tend to gain body fat, but not to the point of becoming obese, with that fat replacing lean body mass yet not forming major visceral deposits. Degenerative diseases are not a big problem when you “shrink” in this way; bigger problems are  accidents (e.g., falls) and opportunistic infections. Often older hunter-gatherers have low blood pressure, no sign of diabetes or cancer, and no heart disease. Still, they frequently die younger than one would expect in the absence of degenerative diseases.

A problem normally faced by older hunter-gatherers is poor nutrition, which is both partially caused and compounded by lack of exercise. Hunter-gatherers usually perceive the Western idea of exercise as plain stupidity. If older hunter-gatherers can get youngsters in their prime to do physically demanding work for them, they typically will not do it themselves. Appetite seems to be negatively affected, leading to poor nutrition; dehydration often is a problem as well.

Now, we know from this post that animal protein consumption does not lead to bone loss. In fact, it seems to increase bone mineral content. But there is something that decreases bone mineral content, as well as muscle mass, like nothing else – lack of physical activity. And there is something that increases bone mineral content, as well as muscle mass, in a significant way – vigorous weight-bearing exercise.

Take a look at the figure below, which I already discussed on a previous post. It shows a clear pattern of benign ventricular hypertrophy in Eskimos aged 30-39. That goes down dramatically after age 40. Remember what Mazess & Mather (1974) said in their article: “… after age 40 the Eskimos of both sexes had a deficit of from 10 to 15% relative to white standards”.

Benign ventricular hypertrophy is also known as athlete's heart, because it is common among athletes, and caused by vigorous physical activity. A prevalence of ventricular hypertrophy at a relatively young age, and declining with age, would suggest benign hypertrophy. The opposite would suggest pathological hypertrophy, which is normally induced by obesity and chronic hypertension.

So there you have it. The reason older Eskimos were found to have lower bone mineral content after 40 is likely not due to their diet.  It is likely due to the same reasons why they "shrink", and also in part because they "shrink". Not only does physical activity decrease dramatically as Eskimos age, but so does lean body mass.

Obese Westerners tend to have higher bone density on average, because they frequently have to carry their own excess body weight around, which can be seen as a form of weight-bearing exercise. They pay the price by having a higher incidence of degenerative diseases, which probably end up killing them earlier, on average, than osteoporosis complications.

Reference

Mazess R.B., & Mather, W.W. (1974). Bone mineral content of North Alaskan Eskimos. American Journal of Clinical Nutrition, 27(9), 916-925.

Vitamin D deficiency, seasonal depression, and diseases of civilization

George Hamilton admits that he has been addicted to sunbathing for much of his life. The photo below (from: phoenix.fanster.com), shows him at the age of about 70. In spite of possibly too much sun exposure, he looks young for his age, in remarkably good health, and free from skin cancer. How come? Maybe his secret is vitamin D.

Vitamin D is a fat-soluble pro-hormone; not actually a vitamin, technically speaking. That is, it is a substance that is a precursor to hormones, which are known as calcipherol hormones (calcidiol and calcitriols). The hormones synthesized by the human body from vitamin D have a number of functions. One of these functions is the regulation of calcium in the bloodstream via the parathyroid glands.

The biological design of humans suggests that we are meant to obtain most of our vitamin D from sunlight exposure. Vitamin D is produced from cholesterol as the skin is exposed to sunlight. This is one of the many reasons (see here for more) why cholesterol is very important for human health.

Seasonal depression is a sign of vitamin D deficiency. This often occurs during the winter, when sun exposure is significantly decreased, a phenomenon known as seasonal affective disorder (SAD). This alone is a cause of many other health problems, as depression (even if it is seasonal) may lead to obesity, injury due to accidents, and even suicide.

For most individuals, as little as 10 minutes of sunlight exposure generates many times the recommended daily value of vitamin D (400 IU), whereas a typical westernized diet yields about 100 IU. The recommended 400 IU (1 IU = 25 ng) is believed by many researchers to be too low, and levels of 1,000 IU or more to be advisable. The upper limit for optimal health seems to be around 10,000 IU. It is unlikely that this upper limit can be exceeded due to sunlight exposure, as noted below.

Cod liver oil is a good source of vitamin D, with one tablespoon providing approximately 1,360 IU. Certain oily fish species are also good sources; examples are herring, salmon and sardines. For optimal vitamin and mineral intake and absorption, it is a good idea to eat these fish whole. (See here for a post on eating sardines whole.)

Periodic sun exposure (e.g., every few days) has a similar effect to daily exposure, because vitamin D has a half-life of about 25 days. That is, without any use by the body, it would take approximately 25 days for vitamin D levels to fall to half of their maximum levels.

The body responds to vitamin D intake in a "battery-like" manner, fully replenishing the battery over a certain amount of time. This could be achieved by moderate (pre-sunburn) and regular sunlight exposure over a period of 1 to 2 months for most people. Like most fat-soluble vitamins, vitamin D is stored in fat tissue, and slowly used by the body.

Whenever sun exposure is limited or sunlight scarce for long periods of time, supplementation may be needed. Excessive supplementation of vitamin D (i.e., significantly more than 10,000 IU per day) can cause serious problems, as the relationship between vitamin D levels and health complications follows a U curve pattern. These problems can be acute or chronic. In other words, too little vitamin D is bad for our health, and too much is also bad.

The figure below (click on it to enlarge), from Tuohimaa et al. (2009), shows two mice. The one on the left has a genetic mutation that leads to high levels of vitamin D-derived hormones in the blood. Both mice have about the same age, 8 months, but the mutant mouse shows marked signs of premature aging.

It is important to note that the skin wrinkles of the mice on the left have nothing to do with sun exposure; they are associated with excessive vitamin D-derived hormone levels in the body (hypervitaminosis D) and related effects. They are a sign of accelerated aging.

Production of vitamin D and related hormones based on sunlight exposure is tightly regulated by various physiological and biochemical mechanisms. Because of that, it seems to be impossible for someone to develop hypervitaminosis D due to sunlight exposure. This does NOT seem to be the case with vitamin D supplementation, which can cause hypervitaminosis D.

In addition to winter depression, chronic vitamin D deficiency is associated with an increased risk of the following chronic diseases: osteoporosis, cancer, diabetes, autoimmune disorders, hypertension, and atherosclerosis.

The fact that these diseases are also known as the diseases of civilization should not be surprising to anyone. Industrialization has led to a significant decrease in sunlight exposure. In cold weather, our Paleolithic ancestors would probably seek sunlight. That would be one of their main sources of warmth. In fact, one does not have to go back that far in time (100 years should be enough) to find much higher average levels of sunlight exposure than today.

Modern humans, particularly in urban environments, have artificial heating, artificial lighting, and warm clothes. There is little or no incentive for them to try to increase their skin's sunlight exposure in cold weather.

References:

W. Hoogendijk, A. Beekman, D. Deeg, P. Lips, B. Penninx. Depression is associated with decreased 25-hydroxyvitamin-D and increased parathyroid hormone levels in old age. European Psychiatry, Volume 24, Supplement 1, 2009, Page S317.

P. Tuohimaa, T. Keisala, A. Minasyan, J. Cachat, A. Kalueff. Vitamin D, nervous system and aging. Psychoneuroendocrinology, Volume 34, Supplement 1, December 2009, Pages S278-S286.