Feeding Your Bones
A Vegan Health Article from All-Creatures.org

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Dr. Mary (Clifton) Wendt, Get Waisted
April 2014

In the digestion process of animal proteins, the proteins must undergo extensive methylation and hydroxylation. These chemical processes result in the creation of acids. The body rids itself of these excess acids by peeing them out in the urine. But in order to neutralize the acidity of the urine, the body grabs extra calcium from the bones and that’s peed out too—in the same way my mom neutralizes her excess acidity by taking a Tums. The advantage vegans hold is that plants do not create an acid environment in the body and, therefore, the body isn’t stimulated to leach calcium from the bones to neutralize the acid.

Bone is made up of proteins that bind to each other, creating strong cross links that support the weight of the other structures in the body, like muscles and organs. There are two types of bone in the human skeleton: Trabecular bone is found in the inside of bones. When it’s healthy, it looks like very good Swiss cheese, or like the steel structure of a skyscraper in the process of being built. The outer layer of bone, the cortex, is made up of cortical bone. Cortical bone is thicker and denser, and functions like a strong outer protective shell for the inner latticework.

What keeps bones strong and healthy, and why do some of us suffer from bone weakness? It all has to do with bone turnover, and that’s a subject keenly interesting to Dr. David Dempster. He is a bone scientist who has spent 40 years studying bone turnover at Cornell University in upstate New York.

Imagine that you just initiated a running program, and that you’ve unfortunately developed micro-fractures in your tibia, commonly referred to as shin splints. I’m going to explain what happens at the cellular level so that you can connect the boring science to the more exciting implications for diet. So here goes! Your body releases molecules that are known as local inflammatory mediators—essentially cells that, like an ambulance, arrive at sites of inflammation to promote healing, cells such as interleukin-1 and tumor necrosis factor. These mediators activate the osteogenic precursor cells—cells that come from bone-forming tissue. These cells then morph into osteoclasts, which are cells that clean up and sweep away dirty, old bone. The osteoclasts swing into action and clean the bone. After the osteoclasts finish their work, they leave behind a resorptive pit, or a space that’s ready to fill in with fresh new bone. Osteoblasts—osteogenic precursor cells that have morphed into building cells—go to the site of the resorptive pit and fill it in with fresh, new bone. The process of building a new bony surface takes only four to six weeks. Mineralizing that site with calcium and phosphorus to harden and strengthen the site takes another several weeks.

In a woman’s premenopausal years, the osteoclastic and osteoblastic functions are beautifully balanced —when old, dirty bone is identified, it is cleaned up and promptly replaced with fresh healthy bone. After estrogen levels decline, however, the osteoclast function—the cells that clean up and sweep away dirty old bone—increases dramatically, but the osteoblast bone-building activities get overwhelmed by bone resorption. There are just not enough osteoblast precursor cells to go around. This results in an overall loss of bone in the postmenopausal woman, particularly in the first three years of menopause.

Bones are remarkably responsive, dynamic structures. Trabecular bone, the inner structure of most bones, turns over at a rate of 22 percent per year. Cortical bone, that outer hard surface of bones, turns over at a rate of only 3 percent per year. When a woman undergoes menopause, however, bone turnover increases by 8 percent for the first three years after the transition, resulting in a remarkably rapid loss of bone early in the menopausal transition.

Protecting the bone through healthy exercise and diet becomes critical during this phase of life. According to Dr. Bonny Specker, the world thought leader on exercise and bone health, the very best exercise for bone building is tennis. There’s plenty of acceleration and rapid deceleration (running and stopping), weighted rotation (swinging the racket) and weight-bearing exercise (jumping) for the entire skeleton. Increasingly, scientists are looking not only at the distance or duration of exercise, but at the acceleration and deceleration that occurs during the exercise. Stopping and starting, like running or basketball may have more skeletal benefits than exercising exclusively with yoga or walking.

Mix It Up

If you aren’t a tennis player, identify a number of different activities you do like to do. Biking is great, but bikers are prone to osteoporosis of the mid-spine due to lack of use. Walking is great too, but it doesn’t work the shoulder girdle and upper spine very well. Combining a few different activities will benefit your entire body’s skeleton and muscle system. This is why so many excellent personal trainers recommend you do a wide range of activities through cross training.

Keep Calcium in Your Bones

Remember Dr. Dempster? Turns out he wrote the paper on nutrition and osteoporosis way back in the 1980s. He studied the function of osteoclasts in great detail. When osteoclasts get ready to sweep away bone, they adhere themselves to the surface of the bone. The osteoclast then creates a pocket of highly acidic fluid between itself and the bone. It is in this highly acidic environment that the osteoclast works to sweep away damaged bone. Dr. Dempster’s laboratory work showed that when the acidity of the microenvironment rose even slightly, the osteoclasts went crazy with increased activity. The acidic microenvironment theoretically makes their job of creating a highly acidic pocket much easier. They are able to work faster to absorb and sweep away bone.

The acidic microenvironment purportedly created by a diet rich in animal proteins theoretically results in accelerated osteoclastic function, according to Dr. Dempster’s research. Remember hearing that meat doesn’t really digest; it just rots in your gut? When a woman eats a diet rich in animal proteins, this results in a prolonged acidic environment in the gut. The increased gut acidity results in increased acidity in the blood.

The body’s chemistry becomes vital when talking about bones, but it’s another one of those subjects that gets complicated fast. Think about it like this: When my mom gets a sour stomach, she often chews a calcium carbonate tablet for instant acid indigestion relief, under the trade name of Tums. This is exactly what the body is doing when it is going to the bone for calcium salts in an effort to neutralize the acidity created by animal foods. But how do animal foods create acid?

In the digestion process of animal proteins, the proteins must undergo extensive methylation and hydroxylation. These chemical processes result in the creation of acids. The body rids itself of these excess acids by peeing them out in the urine. But in order to neutralize the acidity of the urine, the body grabs extra calcium from the bones and that’s peed out too—in the same way my mom neutralizes her excess acidity by taking a Tums. The advantage vegans hold is that plants do not create an acid environment in the body and, therefore, the body isn’t stimulated to leach calcium from the bones to neutralize the acid.

Recent studies, however, have argued that urinary acidification/calcification associated with a high protein diet may not be accurate. These researchers gave women very large doses of animal proteins combined with a large dose of calcium that was radioactively tagged, so they could see where the calcium ended up. They noted that the radioactively tagged calcium ended up in the blood serum and urine after women consumed a large amount of protein. The researchers concluded that the calcium in the urine of women consuming a high protein diet actually originates from the food they are eating, not from their own bones. The research also suggests that a high protein diet leads to increased calcium absorption—that is the intestines of omnivores more readily absorb calcium from food.

This study seems to raise more questions than it answers. If a high protein diet is consumed with high concentrations of calcium, then the body will not have to look to the skeletal system for additional calcium to handle the increased urinary acidity. However, if the woman’s diet is deficient in calcium, as is true in Western diets, then the body will naturally have to look to the skeleton as a source of calcium. Further study in this area, with a more realistic combination of a high protein diet with low calcium ingestion, might provide more insightful on how diet affects skeletal health.

Not all animal proteins are created equal, according to research by Dr. T Colin Campbell and Boston nutrition expert Dr. Beth Dawson-Hughes. Meats and processed dairy products such as hard cheeses generate acid during their digestion. Liquid milk, however, is alkaline in the body, and does not promote urinary acidification and calcification like other dairy products. You still might want to avoid liquid milk for other reasons, but more on that later. It is not reasonable to issue a blanket warning that all animal proteins are harmful to your bones.

PPerhaps the most reassuring bit of data arose from a study of Buddhist nuns, women who were vegans for most or all of their lives. The bone density of these nuns was measured and compared to the bone density of ordinary women. It turns out that the nuns had clinically equivalent bone mineral density to women who drank cow’s milk and consumed nearly twice as much calcium in their daily diet.

To suggest that dairy products aren’t the healthiest source of dietary calcium and protein is almost unpatriotic here in the United States. We Americans grew up as little girls with milk on our cereal at breakfast, a carton of milk on the corner of our lunch tray and a glass of milk at the corner of our placemat at dinner. Copious scientific data have made it clear that we have healthier, safer protein and calcium sources in beans and whole grains, without the inflammation and acidification risks associated with animal proteins. While plenty of government programs subsidize meat and dairy, women have to recognize that the government is often slow to respond to new information. Women seeking optimal health should focus on the identification of plant sources of calcium like green leafy vegetables, whole grains and beans.

Getting to Know Your Skeleton

You can ask your doctor to perform a bone density test to determine the density of your skeleton. Bone density can be measured by ultrasound, plain x-ray or a quantitative CT scanning of the vertebrae (back) or femur (thigh) bone, but the most common method is the use of bone densitometry. The technology is readily available everywhere, and you don’t even have to undress to undergo the testing. You can simply lie down on the examination table while the records your bone density in just a few moments. The radiation exposure is equivalent to a day in the sun. Most advisory boards recommend starting bone density measurements at 65 years old, repeating them as often as necessary based on the bone density measurement, risk for developing osteoporosis and risks for fracture. For example, the need for treatment or frequency of testing is different for a healthy gal who has low bone density, compared to a gal who doesn’t eat properly, smokes, takes multiple medications and who is at risk of falling because of limited vision. Your doctor should carefully balance all of the risks and benefits of therapy before initiating any medical management. You can also use risk calculators available to your doctor through the National Osteoporosis Foundation to help determine your risk of fracture more accurately.

What to Do if You’re Diagnosed with Osteoporosis

Osteoporosis treatment is reasonable when diet and exercise fails to control bone loss, or when bone loss is complicated with fracture. As women age, the main reasons for loss of independence and transfer to nursing homes are dementia and bone fracture. Preventing fracture, therefore, is a very important part of successful aging. To prevent a fall, do the easy things first. Remove any clutter from the floor and tape down or remove any loose carpets or rugs that may get caught on the edge of a foot and lead to falls. Make sure that if you need a walking aid, you use it regularly. If your doctor thinks you would benefit from using a cane, go ahead and buy a cane to stabilize your posture, and then use it. It’ll do you no good propped up against the wall instead of held in your hand.

Long-term treatment with many bone-stabilizing medications is falling under scrutiny recently, since these medications have been linked to atypical fracture in the femur and osteonecrosis of the jaw (bone death caused by poor blood supply). Researchers are concerned that prolonged treatment with osteoporosis medications may result in the suppression of bone turnover until the bone is no longer able to properly heal itself by cleaning up and replacing old, damaged bone. As a result, damaged bone may accumulate, which increases risk for fracture. If you have been treated for many years with osteoporosis medications, it may be time to talk to your doctor.

While there is talk of taking a “drug holiday,” where patients stop their osteoporosis medications for a while, there are no scientific studies to support that idea.

When considering a drug holiday, it’s important to note that adequate data on fracture risk is collected in just three short years of study in most drug trials. If you are osteoporotic at high risk of fracture because of falls or other chronic disease, it doesn’t take long to experience a serious outcome, like fracture and disability, from your osteoporosis. If you have osteoporosis, you are at higher risk for fracture, and given the consequences of fractures, taking prescribed medications makes a lot of sense. The FDA does recommend that potent osteoporosis therapy is limited to three to five years, at which time therapeutic need should be reassessed. There are new medications and alternatives that don’t have the same level of risk associated with their administration, and a little subtle change in your medication, in addition to a great, healthy diet and exercise plan, may be just the thing you need.

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We began this archive as a means of assisting our visitors in answering many of their health and diet questions, and in encouraging them to take a pro-active part in their own health. We believe the articles and information contained herein are true, but are not presenting them as advice. We, personally, have found that a whole food vegan diet has helped our own health, and simply wish to share with others the things we have found. Each of us must make our own decisions, for it's our own body. If you have a health problem, see your own physician.