Why Is Milk Consumption Associated with More Bone Fractures?

Why Is Milk Consumption Associated with More Bone Fractures?.jpg

Milk is touted to build strong bones, but a compilation of all the best studies found no association between milk consumption and hip fracture risk, so drinking milk as an adult might not help bones, but what about in adolescence? Harvard researchers decided to put it to the test.

Studies have shown that greater milk consumption during childhood and adolescence contributes to peak bone mass, and is therefore expected to help avoid osteoporosis and bone fractures in later life. But that's not what researchers have found (as you can see in my video Is Milk Good for Our Bones?). Milk consumption during teenage years was not associated with a lower risk of hip fracture, and if anything, milk consumption was associated with a borderline increase in fracture risk in men.

It appears that the extra boost in total body bone mineral density from getting extra calcium is lost within a few years; even if you keep the calcium supplementation up. This suggests a partial explanation for the long-standing enigma that hip fracture rates are highest in populations with the greatest milk consumption. This may be an explanation for why they're not lower, but why would they be higher?

This enigma irked a Swedish research team, puzzled because studies again and again had shown a tendency of a higher risk of fracture with a higher intake of milk. Well, there is a rare birth defect called galactosemia, where babies are born without the enzymes needed to detoxify the galactose found in milk, so they end up with elevated levels of galactose in their blood, which can causes bone loss even as kids. So maybe, the Swedish researchers figured, even in normal people that can detoxify the stuff, it might not be good for the bones to be drinking it every day.

And galactose doesn't just hurt the bones. Galactose is what scientists use to cause premature aging in lab animals--it can shorten their lifespan, cause oxidative stress, inflammation, and brain degeneration--just with the equivalent of like one to two glasses of milk's worth of galactose a day. We're not rats, though. But given the high amount of galactose in milk, recommendations to increase milk intake for prevention of fractures could be a conceivable contradiction. So, the researchers decided to put it to the test, looking at milk intake and mortality as well as fracture risk to test their theory.

A hundred thousand men and women were followed for up to 20 years. Researchers found that milk-drinking women had higher rates of death, more heart disease, and significantly more cancer for each glass of milk. Three glasses a day was associated with nearly twice the risk of premature death, and they had significantly more bone and hip fractures. More milk, more fractures.

Men in a separate study also had a higher rate of death with higher milk consumption, but at least they didn't have higher fracture rates. So, the researchers found a dose dependent higher rate of both mortality and fracture in women, and a higher rate of mortality in men with milk intake, but the opposite for other dairy products like soured milk and yogurt, which would go along with the galactose theory, since bacteria can ferment away some of the lactose. To prove it though, we need a randomized controlled trial to examine the effect of milk intake on mortality and fractures. As the accompanying editorial pointed out, we better find this out soon since milk consumption is on the rise around the world.

What can we do for our bones, then? Weight-bearing exercise such as jumping, weight-lifting, and walking with a weighted vest or backpack may help, along with getting enough calcium (Alkaline Diets, Animal Protein, & Calcium Loss) and vitamin D (Resolving the Vitamin D-Bate). Eating beans (Phytates for the Prevention of Osteoporosis) and avoiding phosphate additives (Phosphate Additives in Meat Purge and Cola) may also help.

Maybe the galactose angle can help explain the findings on prostate cancer (Prostate Cancer and Organic Milk vs. Almond Milk) and Parkinson's disease (Preventing Parkinson's Disease With Diet).

Galactose is a milk sugar. There's also concern about milk proteins (see my casomorphin series) and fats (The Saturated Fat Studies: Buttering Up the Public and Trans Fat in Meat and Dairy) as well as the hormones (Dairy Estrogen and Male Fertility, Estrogen in Meat, Dairy, and Eggs and Why Do Vegan Women Have 5x Fewer Twins?).

Milk might also play a role in diabetes (Does Casein in Milk Trigger Type 1 Diabetes, Does Bovine Insulin in Milk Trigger Type 1 Diabetes?) and breast cancer (Is Bovine Leukemia in Milk Infectious?, The Role of Bovine Leukemia Virus in Breast Cancer, and Industry Response to Bovine Leukemia Virus in Breast Cancer).

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank / Flickr. This image has been modified.

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Why Is Milk Consumption Associated with More Bone Fractures?

Why Is Milk Consumption Associated with More Bone Fractures?.jpg

Milk is touted to build strong bones, but a compilation of all the best studies found no association between milk consumption and hip fracture risk, so drinking milk as an adult might not help bones, but what about in adolescence? Harvard researchers decided to put it to the test.

Studies have shown that greater milk consumption during childhood and adolescence contributes to peak bone mass, and is therefore expected to help avoid osteoporosis and bone fractures in later life. But that's not what researchers have found (as you can see in my video Is Milk Good for Our Bones?). Milk consumption during teenage years was not associated with a lower risk of hip fracture, and if anything, milk consumption was associated with a borderline increase in fracture risk in men.

It appears that the extra boost in total body bone mineral density from getting extra calcium is lost within a few years; even if you keep the calcium supplementation up. This suggests a partial explanation for the long-standing enigma that hip fracture rates are highest in populations with the greatest milk consumption. This may be an explanation for why they're not lower, but why would they be higher?

This enigma irked a Swedish research team, puzzled because studies again and again had shown a tendency of a higher risk of fracture with a higher intake of milk. Well, there is a rare birth defect called galactosemia, where babies are born without the enzymes needed to detoxify the galactose found in milk, so they end up with elevated levels of galactose in their blood, which can causes bone loss even as kids. So maybe, the Swedish researchers figured, even in normal people that can detoxify the stuff, it might not be good for the bones to be drinking it every day.

And galactose doesn't just hurt the bones. Galactose is what scientists use to cause premature aging in lab animals--it can shorten their lifespan, cause oxidative stress, inflammation, and brain degeneration--just with the equivalent of like one to two glasses of milk's worth of galactose a day. We're not rats, though. But given the high amount of galactose in milk, recommendations to increase milk intake for prevention of fractures could be a conceivable contradiction. So, the researchers decided to put it to the test, looking at milk intake and mortality as well as fracture risk to test their theory.

A hundred thousand men and women were followed for up to 20 years. Researchers found that milk-drinking women had higher rates of death, more heart disease, and significantly more cancer for each glass of milk. Three glasses a day was associated with nearly twice the risk of premature death, and they had significantly more bone and hip fractures. More milk, more fractures.

Men in a separate study also had a higher rate of death with higher milk consumption, but at least they didn't have higher fracture rates. So, the researchers found a dose dependent higher rate of both mortality and fracture in women, and a higher rate of mortality in men with milk intake, but the opposite for other dairy products like soured milk and yogurt, which would go along with the galactose theory, since bacteria can ferment away some of the lactose. To prove it though, we need a randomized controlled trial to examine the effect of milk intake on mortality and fractures. As the accompanying editorial pointed out, we better find this out soon since milk consumption is on the rise around the world.

What can we do for our bones, then? Weight-bearing exercise such as jumping, weight-lifting, and walking with a weighted vest or backpack may help, along with getting enough calcium (Alkaline Diets, Animal Protein, & Calcium Loss) and vitamin D (Resolving the Vitamin D-Bate). Eating beans (Phytates for the Prevention of Osteoporosis) and avoiding phosphate additives (Phosphate Additives in Meat Purge and Cola) may also help.

Maybe the galactose angle can help explain the findings on prostate cancer (Prostate Cancer and Organic Milk vs. Almond Milk) and Parkinson's disease (Preventing Parkinson's Disease With Diet).

Galactose is a milk sugar. There's also concern about milk proteins (see my casomorphin series) and fats (The Saturated Fat Studies: Buttering Up the Public and Trans Fat in Meat and Dairy) as well as the hormones (Dairy Estrogen and Male Fertility, Estrogen in Meat, Dairy, and Eggs and Why Do Vegan Women Have 5x Fewer Twins?).

Milk might also play a role in diabetes (Does Casein in Milk Trigger Type 1 Diabetes, Does Bovine Insulin in Milk Trigger Type 1 Diabetes?) and breast cancer (Is Bovine Leukemia in Milk Infectious?, The Role of Bovine Leukemia Virus in Breast Cancer, and Industry Response to Bovine Leukemia Virus in Breast Cancer).

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank / Flickr. This image has been modified.

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What to Eat to Protect Against Kidney Cancer

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58,000 Americans are diagnosed with kidney cancer every year, and 13,000 die. And the numbers have been going up. Approximately 4 percent of cases are hereditary, but what about the other 96 percent? The only accepted risk factor has been tobacco use, but cigarette smoking has been declining.

Nitrosamines are one of the most potent carcinogens in cigarette smoke. One hot dog has as many nitrosamines and nitrosamides as five cigarettes. And these carcinogens are also found in fresh meat as well: beef, chicken and pork. So even though smoking rates have dropped, perhaps the rise in kidney cancer over the last few decades may have something to do with meat consumption. But would kidney cancer just be related to the processed meats like bacon, sausage, hot dogs and cold cuts that have nitrate and nitrite additives, or fresh meat as well?

The NIH-AARP study featured in my video Can Diet Protect Against Kidney Cancer? is the largest prospective study on diet and health ever performed--about 500,000 followed for nine years. In addition to examining nitrate and nitrite intake from processed meat, they also looked at intake from other sources such as fresh meat, eggs and dairy. Nitrite from animal sources, not just processed meats, was associated with an increased risk of kidney cancer, and total intake of nitrate and nitrite from processed meat sources was also associated with kidney cancer risk. The researchers found no associations with nitrate or nitrite intake from plant sources, but nitrates from processed meat was associated with cancer.

When meat producers advertise their bacon or lunch meat as "uncured," this means no nitrites or nitrates added. But if you look at the small print you'll see something like, "except for celery juice." That's just a sneaky way to add nitrites. Processed meat producers ferment the nitrates in celery to create nitrites, then add it to the meat; a practice even the industry admits "may be viewed as incorrect at best or deceptive at worst."

But that same fermentation of nitrates to nitrites can happen thanks to bacteria on our tongue when we eat vegetables. So why are nitrates and nitrites from vegetables on our tongue harmless, but nitrates and nitrites from vegetables in meat linked to cancer? The actual carcinogens are not nitrites, but nitrosamines and nitrosamides. In our stomach, to turn nitrites into nitros-amines, and nitros-amides we need amines and amides, which are concentrated in animal products. And vitamin C and other antioxidants in plant foods block the formation of these carcinogens in our stomach. That's why we can safely benefit from the nitrates in vegetables without the cancer risk. In fact some of the highest nitrate vegetables like arugula, kale, and collards are associated with decreased risk of kidney cancer. The more plants, it appears, the better.

Plant-based diets and fiber-rich diets are recommended to prevent cancer directly, as well as chronic conditions associated with kidney cancer, such as obesity, high blood pressure and diabetes. It's similar to sodium intake and kidney cancer. Sodium intake increases kidney disease risk, but that's not just because sodium intake increases blood pressure. It appears the salt is associated with increased cancer risk even independently of hypertension. What about plant-based diets? Turns out the protective association remains even in people who are not obese and have normal blood pressure. So overall, plant-based and fiber-rich diets appear to do both: decrease cancer risk directly and indirectly.

I briefly address kidney health in Preventing Kidney Failure Through Diet and Treating Kidney Failure Through Diet, but have a whole series of more in-depth videos dealing with various kidney issues.

More on the fascinating nitrate/nitrite story in my 17-part series about improving athletic performance with nitrate-rich vegetables such as beets and arugula. Here are a few short highlights:

More on carcinogens caused by cooking meat in videos like:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: RDSVS / Flickr

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How Fruits and Vegetables Can Prevent Asthma

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Asthma is the most common chronic disease in children and the prevalence is increasing around the world. Despite this, most research dollars are spent on adult chronic disease. "One might ask," a group of researchers posited "whether this is because our politicians and senior administrators feel themselves to be more likely to suffer from the latter, and thus ignore allergic diseases as they mostly impact children and young adults" - who don't vote.

An enormous study about asthma and allergies in childhood, highlighted in my video, Preventing Asthma with Fruits and Vegetables, was published that includes more than a million children in nearly a hundred countries, making it the most comprehensive survey of asthma and allergies ever undertaken. The researchers found striking worldwide variations in the prevalence and severity of asthma, allergies, and eczema--a 20 to 60-fold difference in prevalence of symptoms of asthma, allergic runny nose, and atopic eczema around the world. The large variability suggests a crucial role of local characteristics that are determining the differences in prevalence between one place and another.

What kind of environmental factors? Why does the prevalence of itchy eyes and runny noses range anywhere from 1% in India, for example, and up to 45% of kids elsewhere? There were some associations with regional air pollution and smoking rates, but the most significant associations were with diet. Adolescents showed a consistent pattern of decreases in symptoms of wheeze (current and severe), allergic rhinoconjunctivitis, and atopic eczema with increases in per capita consumption of plant foods. The more their calories and protein came from plant sources, the less allergies they tended to have.

In general, there seems to be an association between an increase in asthma prevalence and a decrease in consumption of fresh fruits, green vegetables, and other dietary sources of antioxidants, helping to explain why the prevalence of asthma and respiratory symptoms are lower in populations with high intake of foods of plant origin. High intakes of fat and sodium, and low intakes of fiber and carbohydrates, are linked with asthma, while traditional and vegetarian diets are associated with lower rates. For example, if we look closer within India, in a study of more than 100,000 people, "those who consumed meat (daily or occasionally) were more likely to report asthma than those who were strictly vegetarian." This also meant avoiding eggs.

Eggs have been associated (along with soft drink consumption) with increased risk of respiratory symptoms and asthma in schoolchildren. On the other hand, consumptions of soy foods and fruits were associated with reduced risk of respiratory symptoms. In fact, removing eggs and dairy from the diet may improve lung function in asthmatic children in as little as eight weeks. Therefore, it may be a combination of eating fewer animal foods and more plants.

High vegetable intake, for example, has been found protective in children, potentially cutting the odds of allergic asthma in half. And fruit has also shown a consistent protective association for current and severe wheeze and runny nose in adolescents, and for current and severe asthma, allergies, and eczema in children.

Why is this? I've talked about the endocrine-disrupting industrial pollutants (see Dietary Sources of Alkylphenol Endocrine Disruptors) building up in the meat supply that may increase the risk of allergic disease, but the increase in asthma may be a combination of both a more toxic environment and a more susceptible population. One review notes that, "The dietary changes which have occurred over recent years may have led to a reduction in these natural antioxidant defenses, resulting in a shift of the antioxidant status of the whole population and leading to increased susceptibility to oxidant attack and airway inflammation."

In adults, for example, the risk of airway hyper-reactivity may increase seven-fold among those with the lowest intake of vitamin C from plant foods, while those with the lowest intake of saturated fats may have a 10-fold protection, presumably because of saturated fat's role in triggering inflammation.

The protective effect of plant-based food may also be mediated through effects on intestinal microflora. It turns out that differences in the indigenous intestinal flora might affect the development and priming of the immune system in early childhood. Kids with allergies, for example, tend to be less likely to harbor lactobacilli, the good bacteria that's found in fermented foods, and naturally on many fruits and vegetables. Lactobacillus probiotics may actually help with childhood asthma, which may help explain why children raised on largely organic vegetarian diets may have a lower prevalence of allergic reactions. Infants raised this way tend to have more good lactobacilli in their guts compared to controls, though they were also more likely to have been born naturally, breastfed longer, and not been given antibiotics, so we can't really tell if it's the diet until we put it to the test (See Treating Asthma with Fruits and Vegetables).

More on preventing allergic diseases can be found in my videos Preventing Childhood Allergies and Preventing Allergies in Adulthood.

More on protecting lung function with fruits and vegetables can be found in Preventing COPD With Diet.

Surprised probiotics can affect immune function? Check out my video Preventing the Common Cold with Probiotics? And if you think that is wild, wait until you see Gut Feelings: Probiotics and Mental Health.

What might be in plants that's so beneficial? See Anti-inflammatory Antioxidants.

What might be in animal products that is harmful to lung function? There are endocrine-disrupting industrial pollutants that build up in the food chain that may be playing a role. See my video Alkylphenol Endocrine Disruptors and Allergies. Also there's an inflammatory omega-6 fatty acid found predominantly in chicken and eggs that may contribute to inflammation as well. See Inflammatory Remarks About Arachidonic Acid.

Choosing fragrance-free personal care products may also help reduce airway reactivity: Throw Household Products Off the Scent.

I compare the efficacy of plants to pills (Treating Asthma With Plants vs. Supplements?) and explore the role an entire diet filled with plants might play in Treating Asthma and Eczema With Plant-Based Diets.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: EdTech Stanford University School of Medicine / Flickr

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