Note: this article is co-authored by Jack Norris, RD and Ginny Messina, MPH, RD and appears on Ginny’s blog as well as this one.

Vegans typically have lower calcium intakes than other vegetarians and meat-eaters. But just how much does this matter?

The popular thinking has long been that it doesn’t matter much at all. According to the acid-ash hypothesis of osteoporosis, vegans experience smaller calcium losses since we don’t eat animal protein. The theory is that calcium is “leached” from bones to counter acidic conditions caused by animal protein.

It’s supported by studies that find higher levels of both calcium and acidic compounds in the urine when people are fed big doses of animal protein (1). This is also supposedly why hip fracture rates are higher in countries with high animal protein intakes (2).

But while the theory had great support several decades ago, it hasn’t held up to the scientific evidence. An article by vegan dietitian Dr. Reed Mangels, based on a presentation she gave at the Sixth International Congress on Vegetarian Nutrition sums up the more recent research very well (3). It should be required reading for all vegan and vegetarian nutrition professionals.

Unfortunately, a quick Google search of “vegan-calcium-bone-health” shows that many vegan educators, including some who are health professionals, are still promoting the idea that protein causes calcium loss from bones.

We thought it would be interesting to see where vegetarian dietitians fit into all of this. So, we created a true/false questionnaire about bone health, protein and vegan diets. We asked dietitians who subscribe to the email list for the Vegetarian Nutrition Dietetic Practice Group (VNDPG) to answer the questions.

Although this was a small, unscientific survey, the results were interesting. They showed that VNDPG members were more aware of the issues than the general vegan community and are sharing better information than what is often available on the internet and elsewhere. But in some cases, even RDs weren’t aware of the newer research on protein and bone health.

Here is the survey with our answers.

1. Protein contributes to bone structure. TRUE

Most RDs got this one right. Bone contains collagen and other proteins and you can’t build and maintain bones without protein (4).

2. Protein from animal foods causes calcium loss from bones. Probably FALSE

According to a 2009 meta-analysis of epidemiological studies, protein is not harmful to bone health and may be beneficial (5). Particularly relevant to vegetarians, in the Adventist Health Study-2, vegetarians who ate the most protein-rich foods like legumes and veggie meats, had the fewest fractures (6). It’s true that studies link higher protein intake with higher urinary calcium losses. But this is in response to eating isolated proteins, not protein-rich foods (7). The phosphorus in those higher-protein foods seems to cancel out the effect on bone loss. Protein also improves calcium absorption when calcium intakes are low (8), so it’s possible that the higher amounts of calcium in the urine simply reflect that greater amounts being absorbed from the diet.

In fact, another 2009 meta-analysis—this one looked at clinical studies—found that the amount of calcium lost in the urine didn’t correlate with calcium balance in the body or with markers of bone health (9). That is, acidic conditions didn’t produce a net loss of calcium from the bones.

The studies comparing hip fracture rates among countries have also been called into question. Since they’re ecological studies, they don’t control for anything and are only marginally useful.

Better information comes from The Hong Kong Osteoporosis Study. This research found that hip fracture rates were lower in Hong Kong than Sweden but that spinal fracture rates were higher (10). And while that seems conflicting, it’s really not. Hip fracture rates are affected less by bone health and more by the likelihood of falling. Spinal fractures, on the other hand, actually reflect bone health. In fact, the researchers said that despite lower hip fracture rates, the Hong Kong women had more osteoporosis.

3. Drinking cow’s milk promotes osteoporosis. Probably FALSE but maybe TRUE

Given the discussion above, it doesn’t seem that the protein in milk would raise risk for osteoporosis. But, research published just last week did raise questions about the effects of milk-drinking on bone health.

The Swedish researchers found that women who drank more than 3 glasses of milk per day had a much higher rate of fracture than those who drank less than a serving (11). In contrast, though, they found that cheese and yogurt were associated with lower rates of fracture. Earlier research in Adventists also found a protective effect of cheese on bone health (12).

One possible explanation, according to the Swedish researchers, is that the sugar galactose—high in milk, but low in cheese and yogurt—is the factor affecting fractures. The research supporting this is in animals, though.

Although it would be premature to say that milk raises fracture risk, there isn’t much evidence that milk-drinkers have any particular health advantage, either. Since we oppose dairy consumption on ethical grounds, it seems like it’s enough to know that nobody actually needs dairy foods in their diet.

4. Research shows that vegans have fewer bone fractures than meat-eaters. FALSE

What evidence we have for this — and admittedly, it’s very little — isn’t especially favorable for vegans. In the EPIC-Oxford study, vegans had a 30% higher risk for fracture after adjusting for numerous variables like age, smoking, alcohol consumption, and physical activity. After adjusting for calcium intake, however, there was no difference in fracture rates. Vegans who got enough calcium were no more likely to break a bone than milk-drinkers (13).

Likewise, in the Adventist Health Study-2, there was a trend toward higher fracture rates among the vegans compared to other vegetarians as well as non-vegetarians (6). (This study didn’t test for statistical significance.)

5. People eating plant-based diets have lower calcium needs than meat-eaters. Probably FALSE

If protein doesn’t have a negative effect on bone health, then there is no reason to think that vegans have lower calcium needs. The EPIC-Oxford study mentioned above suggests that the lower calcium intakes that are typical of vegans may be harmful.

6. The US RDAs for calcium are similar to the World Health Recommendations. TRUE

A common belief is that the WHO recommends just 400 to 500 milligrams of calcium per day. But, the WHO recommends 1000 mg of calcium for adults which is the same as the US RDAs.

Two last questions on our survey looked at the more holistic story of diet and bone health.

7. Weight-bearing exercise is important for bone health TRUE

8. A variety of nutrients including vitamin D, potassium, magnesium, and calcium is needed for healthy bones. TRUE

No surprise that 100% of our respondents knew that bone health is about much more than calcium. No single nutrient or food can make or break the strength of your bones. Keeping bones strong takes a whole diet and lifestyle approach. Getting enough calcium is just one part of that, but it is still an important part. Right now, there is no reason to think that vegans have any particular advantage where this is concerned.

References

1. Schuette SA, Linkswiler HM. Effects on Ca and P metabolism in humans by adding meat, meat plus milk, or purified proteins plus Ca and P to a low protein diet. J Nutr 1982;112:338-49.

2. Frassetto LA, Todd KM, Morris RC, Jr., Sebastian A. Worldwide incidence of hip fracture in elderly women: relation to consumption of animal and vegetable foods. J Gerontol A Biol Sci Med Sci 2000;55:M585-92.

3. Mangels AR. Bone nutrients for vegetarians. Am J Clin Nutr 2014;100:469S-475S.

4. Boskey AL, Coleman R. Aging and bone. J Dent Res 2010;89:1333-48.

5. Darling AL, Millward DJ, Torgerson DJ, Hewitt CE, Lanham-New SA. Dietary protein and bone health: a systematic review and meta-analysis. Am J Clin Nutr 2009.

6. Lousuebsakul-Matthews V, Thorpe DL, Knutsen R, Beeson WL, Fraser GE, Knutsen SF. Legumes and meat analogues consumption are associated with hip fracture risk independently of meat intake among Caucasian men and women: the Adventist Health Study-2. Public Health Nutr 2013:1-11.

7. Spencer H, Kramer L, DeBartolo M, Norris C, Osis D. Further studies of the effect of a high protein diet as meat on calcium metabolism. Am J Clin Nutr 1983;37:924-9.

8. Kerstetter JE, O’Brien KO, Insogna KL. Dietary protein affects intestinal calcium absorption. Am J Clin Nutr 1998;68:859-65.

9. Fenton TR, Lyon AW, Eliasziw M, Tough SC, Hanley DA. Meta-analysis of the effect of the acid-ash hypothesis of osteoporosis on calcium balance. J Bone Miner Res 2009;24:1835-40.

10. Bow CH, Cheung E, Cheung CL, Xiao SM, Loong C, Soong C, Tan KC, Luckey MM, Cauley JA, Fujiwara S, et al. Ethnic difference of clinical vertebral fracture risk. Osteoporos Int 2012;23:879-85.

11. Michaelsson K, Wolk A, Langenskiold S, Basu S, Warensjo Lemming E, Melhus H, Byberg L. Milk intake and risk of mortality and fractures in women and men: cohort studies. Bmj 2014;349:g6015.

12. Matthews VL, Knutsen SF, Beeson WL, Fraser GE. Soy milk and dairy consumption is independently associated with ultrasound attenuation of the heel bone among postmenopausal women: the Adventist Health Study-2. Nutr Res 2011;31:766-75.

13. Appleby P, Roddam A, Allen N, Key T. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. Eur J Clin Nutr 2007;61:1400-6.

Dr. Michael Greger has posted a very interesting video, Treating Alzheimer’s with Turmeric.

He has also just released Latest in Clinical Nutrition: Volume 21 which includes four videos on the safety of GMOs.

If you’ve read my blog for long, you know that I mostly feature articles summarizing published research. But every now and then I like to have some fun that doesn’t involve comparing risk ratios and statistical significance.

I’ve known Ryan Henn since he organized the Vegans in Vegas conference in 2011. As serendipity would have it, he moved to the Sacramento area in 2012, right around the time I also moved back to the area. I actually never thought of Ryan as particularly out of shape but one day I ran into him and he was strikingly buff. I asked how he did it and thought his story was quite interesting, and he graciously agreed to write an article for my blog. I hope you will enjoy it!

How I Transformed my Body in Seven Steps
by Ryan Henn

For most of my life I’ve been fat. Not heavy, not rotund, stout, or any other euphemism you can toss out. No, I was fat. At age 18 I topped out at more than 300 pounds. Now a lot of that was due to chronic health issues, but my love of fatty meats, cheese, and refined food – and lots of it – was the major factor. By incorporating exercise and making small dietary changes, I was able to drop down to the 200-220 range by my early 20s. Even after adopting a plant based diet in 2004, I struggled with my weight, occasionally dropping down a few pounds only to watch them creep right back on.

In late 2013 I had my body fat measured using a dunk tank, also known as hydrostatic testing. I’d been working out pretty consistently through the years and figured I was in the 16 percent range. Turned out I was pretty far off as I was actually 20.1 percent; far from where I wanted to be. That meant I was carrying around about 40 pounds of fat, enough to fuel my body for more than a month and a half without eating a single bite of food. I knew it was time for a change. I renewed my commitment to getting fit and undertook a fitness challenge, vowing to lose the flab by the start of summer. So beginning in mid-December 2013 at 205 pounds, I began to buckle down with a cleaner diet and hit the weight room regularly. When summer arrived I had my body fat retested. I’d dropped down to 175 pounds and 7.1 percent body fat. That meant in six months time I’d lost more than 28 pounds of fat and also gained about four pounds of muscle.

I thought it might be helpful to others if I shared some of the lessons I learned during my weight loss journey. I’m no expert and I’m not pretending to be. In fact, I’m just getting started on my own fitness goals. There are many paths to getting fit and my only intention is to share the road I took in hopes that it will inspire you.

So here are the seven steps I used to transform my body:

#7 – Eat plants – lots of them

I’ve eaten a plant based (vegan) diet for nearly a decade. Despite this, I’ve always struggled with my weight. Let’s face it, just because it’s vegan doesn’t mean it’s good for you. Oreos are vegan. Enough said. Even though I actually ate pretty clean to begin with, and already limited my enjoyment of overly refined foods, I still couldn’t drop the pounds. I’ve always had a big appetite and get enjoyment from eating, which makes portion control difficult. However, compared with eating the standard American diet, I’ve found being vegan makes it much easier to stay within striking distance of my goal weight. Most natural plant foods tend to be lower in fat and calories while also containing a lot more fiber to fill you up. And of course, in addition to being very healthy, a vegan diet is also much better for the planet and our animal friends. I loaded up daily on green smoothies, peas, broccoli, zucchini, eggplant and squash.

#6 – Cut the cardio

I hate cardio. There I said it. Does that make me a weight loss heretic? Well, so be it. Turned out cardio was completely unnecessary in my success. I experimented with it at times to see if I could boost fat loss or stimulate my metabolism. And what did these efforts get me? Tired legs, poor sleep, and dramatically decreased recovery time. If you love running, keep doing it, but don’t think cardio is the only way to drop weight.

#5 – Eat those carbs!

Working out makes me hungry. That’s good since eating around your exercise session is ideal. Meals consumed pre-exercise help fuel your workout and meals afterwards help repair the damage inflicted. I typically worked out in the evening and always consumed 1/3rd or more of my calories post training. Post workout is also when I’d load up on carbs, although I also ate them throughout the day.

I found limiting my carbs killed my recovery and turned me into a general grump monster. So I aimed to get 40-50% of my daily calories from mostly healthy complex carb sources. The exception was post workout when I’d consume some sugary cereal and usually had a slice or two of whole multigrain bread with my dinner. The rest of the time I stuck to fruit, oatmeal, brown rice and the like. I aimed for a gram of protein per pound of bodyweight or roughly 25-30% of calories which left about 20-25% of calories from fat.

#4 – Stop cheating yourself out of results

There are a ton of questionable fitness articles on the web. Many of them proclaim that cheating on your diet with either a cheat meal or entire cheat day can boost your metabolism and help you drop fat faster. Of course they never have any hard science to back this up. I’m here to tell you it didn’t work for me. All it did was delay my progress and make it difficult to figure out if I was losing weight. Now, I’m not saying you should never “cheat” with a high calorie meal or day. I did and I think you should too. But not every three days and not even every week. At first I tried different schedules and carb cycling routines. However, what ultimately worked best for me was to listen to my body. In the beginning, about every two weeks and then about every week towards the end, I’d start getting hungry, like really really hungry. So I’d plan a day to eat at or above my maintenance calorie level and load up on carbs while trimming my fat intake back as far as possible. These excess carbs were used to fill up my depleted glycogen stores while not piling on a lot of excess fat. Chowing down on pizza and fries won’t give you this same effect and will just pack back on some padding (trust me, I learned this one the hard way).

#3 – Calorie counting sucks but you should do it anyway

All the tips and training in the world won’t do you a bit of good if you can’t control the basics – calories in vs. calories out. I struggled in the beginning and while I was losing weight, it was at a pretty slow rate. I was tracking calories consumed but had to make educated guesses about how many calories I was burning daily. Then I learned about the Bodymedia Fit (www.bodymedia.com) and it changed my whole life. Ok, not really. But it made losing weight so much simpler. You wear the Fit around your upper arm and it tracks energy expenditure to within a 5-10 percent margin of error. By showing you how many calories you’re burning, you can adjust your daily food intake accordingly to make sure you’re achieving your desired calorie deficit. If your deficit is too much, you will start to metabolize muscle for energy (see Calculating the Daily Calorie Deficit For Maximum Fat Loss). You can also see for yourself what does and doesn’t boost your metabolism and how many calories you are actually burning doing all that cardio. Turns out it’s probably a lot less than you think. I found it much easier to create a calorie deficit by reducing the amount of food I ate than by trying to pile cardio onto my weight lifting. I also knew that if I was hitting my daily deficit, daily fluctuations on the scale didn’t mean anything. Thus I was able to skip a lot of the second guessing and head games that can accompany dieting.

#2 – I don’t care about your politics so long as you’re a progressive in the weight room

Progressive overload is the concept that you should always be pushing yourself to be a bit better each workout. That means adding a bit of weight or an extra rep. Doing the same thing you did last week or last month just isn’t good enough. And if you’re not adding plates to the bar or pumping out an extra rep here and there, then it’s likely your recovery isn’t optimal. For me that meant I either wasn’t sleeping enough, wasn’t eating enough, or wasn’t resting enough.

For anyone who cares – or is even still reading at this point – I hit the weights 5-6 days a week using a three or four day body part split for about an hour each session. The body parts were split as: chest and triceps; back and biceps; shoulders, traps and abs; legs and calves. Roughly, I typically do 12-16 sets total per large muscle group broken into 3-4 sets per exercise (for legs, I count squats and dead lifts as both quads and hamstring exercises).

I alternate heavy and light workouts. For example, if I worked chest twice in one week I’d have a heavy day where I worked in the 2-8 rep range and a lighter day where I worked in the 8-15 rep range. This worked awesome and I was consistently able to add weight to all my lifts.

This sort of workout system might not be for everyone. The article Muscle and Muscle Fibers explains how to test your muscle fiber type to determine which workouts will be the best for stimulating your muscles.

#1 – Tank tops

Yep, tank tops are the key to everything. They’re light, breezy, sexy, and fun to wear. Plus everyone looks awesome in the gym if they wear a tank top – especially a Team Vegan tank top from Vegan Outreach!

In all seriousness, getting fit should be fun. Pick activities that you love to help ensure you stick to them. For me that meant lifting weights. But if you love running, cycling, hiking, or playing sports, then do that instead. While dropping weight wasn’t always easy and it required sacrifices at times, both from myself and my family, it was a ton of fun. There’s nothing as amazing as watching your body transform before your eyes.

I hope you’ve learned something from these tips and are inspired to embark on your own fitness quest. And remember, getting fit isn’t just about hitting a specific goal, it’s about the journey to get there. Oh, and be sure to pack a tank top or two just in case. You never know where your road to fitness might take you.

If you’d like more information or have any questions, always feel free to contact me at ryandhenn@gmail.com or on Facebook at www.facebook.com/ryan.henn.

Useful Links:

Body Media – for monitoring energy expenditure
New Grip – non-leather workout gloves
Vegan Weightlifting: What Does the Science Say?

There is a group of researchers in Japan who regularly publish papers in scientific journals about plant sources of vitamin B12. Fumio Watanabe is often the lead researcher, so I refer to them as the “Watanabe group.”

Some of their papers analyze the B12 in foods such as mushrooms, algae, and black tea, while other papers are just review articles of previous research. The latter is the case with their latest paper, Vitamin B12-containing Plant Food Sources for Vegetarians, published in the May 5, 2014 issue of Nutrients (1). A free version can be obtained at the link.

When the Watanabe group analyzes a food for B12, they often find molecules that they believe to be the vitamin. But a complication with simply finding B12 in food is that the food might also contain inactive B12 analogues that interfere with active B12. The Watanabe group is well aware of this and often analyzes the food for some of the typical inactive B12 analogues. Sometimes they feed the food to rats to see if it lowers the rats’ methylmalonic acid (MMA) levels, the prime indicator of B12 activity. Based on how much active B12 and inactive analogues they find, and any results with rats, they make recommendations as to whether a food can provide B12 for vegans.

In their latest review, based on the results of their various experiments combined with a study in which six vegan children stayed healthy eating large amounts of seaweed (my analysis here), they suggest that nori is a “suitable” source of B12 for vegans.

The biggest flaw in this theory is that there is a study that tested raw and dried nori using the gold standard of lowering MMA levels in humans (2), and although the authors of this study were optimistic about raw nori, the fact was that both dried and raw nori reduced B12 status in their subjects.

I often hear from people who say they have been vegan for some time, have not supplemented with B12, and are not B12 deficient. They take this to mean that vegans don’t need a supplemental source of B12. In most cases they do not know whether, in fact, they are B12 deficient or not, because they haven’t been appropriately tested for deficiency. And once you go vegan without a source of B12, you never know when deficiency symptoms might kick in – someone can be fine for years and then one day they start to feel tingling in their fingers or toes or they become severely fatigued. You don’t want to end up like any of the vegans listed in the Individual Cases of Deficiency.

There is also the problem of subclinical B12 deficiency where someone doesn’t feel any symptoms but has mild deficiency for years that can possibly develop into dementia or a stroke. As the Watanabe group says in their latest paper:

“However, Vitamin B12 deficiency may go undetected in vegetarians because their diets are rich in folic acid, which may mask vitamin B12 deficiency until severe health problems occur. Vitamin B12 deficiency contributes to the development of hyperhomocysteinemia, which is recognized as a risk factor for atherothrombotic and neuropsychiatric disorders, thereby negating the beneficial health effects of a vegetarian lifestyle.”

This does not mean that vegans need to get tested for B12 deficiency. On the contrary, I don’t see any need for that unless you decide not to supplement with B12 according to the recommendations here or you are supplementing but experiencing symptoms of B12 deficiency.

Whenever I post about B12, it is inevitable that someone, I suspect an internet troll in many cases, will pipe in to say that cyanocobalamin is not a good source of B12 but that methylcobalamin is. Except in very rare cases, this is not true (see Methylcobalamin & Adenosylcobalamin for more information). If you decide to rely on methylcobalamin, I recommend at least 1,000 µg per day.

If this post interested you, you might also want to read my August 2013 post about the Watanabe group, B12 in Plants and Algae Update.

In conclusion, there is no new evidence to suggest that nori is a reliable source of B12 for vegans and I advise against relying on it.

References

1. Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-containing plant food sources for vegetarians. Nutrients. 2014 May 5;6(5):1861-73. | link

2. Yamada K, Yamada Y, Fukuda M, Yamada S. Bioavailability of dried asakusanori (porphyra tenera) as a source of Cobalamin (Vitamin B12). Int J Vitam Nutr Res. 1999 Nov;69(6):412-8. | link

Dr. Michael Greger of NutritionFacts.org has just released Latest in Clinical Nutrition: Volume 20. Lots on gluten in this one!

Ginny Messina has a great article on the latest wave of ex-vegans listening to their bodies in Disordered Eating, Restrictive Eating, and Ex-Vegans.

The Vegetarian Resource Group just posted What is the Amount of Oxalate in Seitan?

Dr. Kim A. Williams, the president-elect of the American College of Cardiology, suggests that patients go vegan in the New York Times article, Advice From a Vegan Cardiologist.

Two recent studies on avocados have made this dietitian start eating more.

The first was conducted at Ohio State University and examined whether eating avocado could increase vitamin A levels in the blood after meals (1).

Vitamin A is obtained from plant foods by eating carotenoids which the body can then convert into vitamin A. There is evidence that adding fat to meals can increase carotenoid absorption, which isn’t surprising given that carotenoids are fat-soluble. (See the VeganHealth.org article about Vitamin A for more info.)

The study showed that not only did adding 1/2 of an avocado to a high-carotenoid meal increase the amount of carotenoids absorbed, it also increased the amount of vitamin A in the blood by about 3 to 6 times compared to a high-carotenoid meal without avocado.

Some caveats:

– It’s not clear that the amount of vitamin A measured in the blood after a meal really indicates that someone has better vitamin A status.

– Some people are, apparently, “non-responders” and do not absorb more carotenoids when added to the diet. In this study, one participant (out of twelve) was found to be a non-responder and she was removed.

– The Hass Avocado Board provided some of the support for this study.

Increasing vitamin A isn’t necessarily needed by most people, but since vegans do not get a direct source of vitamin A, and many may not eat enough carotenoids, adding avocado to meals will help ensure that you’re efficiently utilizing carotenoids.

And why not? Avocados are delicious.

Of course, there is a reason why not – because avocados are high in fat.

It turns out that due to their high water and fiber content, avocados barely rise to the category of a medium energy dense food. A serving size is considered 1/2 of a medium-sized avocado or 70 g. One serving contains 4.6 g of fiber, 10 g of fat, but only 112 calories. As an extra bonus, it contains 340 mg of potassium (almost as much as a medium-sized banana).

This brings us to the second study, from Loma Linda University, looking at energy intake and satiety (feeling satisfied) when avocados are added to the diet (2).

There were three test meals: a control lunch without avocado, a lunch with the same amount of calories as the control lunch and including 1/2 of an avocado, and a control lunch plus 1/2 of an avocado.

The lunches with the avocados resulted in slightly less hunger over the next three hours, and the people who ate avocados with lunch ate less calories for their evening meal and snack (1194 vs. 1276 kcal; difference was not statistically significant). The meals in which avocado replaced other calories were the winners as those people ate 83 calories less for the day.

Again, there are caveats:

– This doesn’t mean that eating an avocado every day will lead to weight loss. At the very least, it’s evidence that adding one-half of an avocado a day won’t lead to eating more calories for most people.

– In the words of the authors, “The funding for this study was supported by a grant from the Hass Avocado Board, which had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review or approval of the manuscript.”

Any time a study is supported by an industry group you have to be more skeptical. Even if the Hass Avocado Board had nothing to do with conducting the study, there may be an unconscious bias for a positive analysis. In this case, the Loma Linda University researchers suggest that a longer trial is needed “to evaluate the effects of daily avocado intake on measures of appetite sensation and weight management in free-living normal weight, overweight and obese adults.” In other words, it would be great if the Hass Avocado Board could fund some more research.

But that said, who else is going to fund studies like these? We might have to wait a long time before the government makes studying avocados a priority.

When I go to Chipotle, which is every few weeks, I normally ask them to really limit the guacamole they add. It can be comical how large the servings there get as ingredients pile up and by the time they get to the last item, the guacamole, there is already a massive amount of food on the tray, so I’m not inclined to change my ordering habits there.

But Chipotle aside, the research above has already made me add more avocado to my daily eating habits. Congratulations to the Hass Avocado Board – you’ve made a believer out of me!

References

1. Kopec RE, Cooperstone JL, Schweiggert RM, Young GS, Harrison EH, Francis DM, Clinton SK, Schwartz SJ. Avocado Consumption Enhances Human Postprandial Provitamin A Absorption and Conversion from a Novel High-β-Carotene Tomato Sauce and from Carrots. J Nutr. 2014 Aug;144(8):1158-66. | link

2. Wien M, Haddad E, Oda K, Sabaté J. A randomized 3×3 crossover study to evaluate the effect of Hass avocado intake on post-ingestive satiety, glucose and insulin levels, and subsequent energy intake in overweight adults. Nutr J. 2013 Nov 27;12:155. | link

We just added a new child to the Real Vegan Children page. This page lists kids who have been “vegan since conception.” The new child is Zander Earl and his mother provides an interesting and extensive write-up.

Dr. Greger recently highlighted an exciting study at NutritionFacts.org in his video, Preventing Prediabetes By Eating More. In this study, adding 5 cups of pulses (beans and peas) per week to the diets of people at risk for type 2 diabetes resulted in improvements similar to counseling patients to reduce food intake by 500 calories per day.

Dr. Greger also recently came out with a new DVD, Dr. Greger’s 2014 Year-in-Review Presentation.

Ginny Messina posted an interesting article, Vegans Drink Almond Milk Because It’s Cruelty-Free–Not Because It’s Hip. Excerpt:

“I like almond milk, but I rarely drink it. I actually don’t drink plant milk much at all, but when I do, it’s always soymilk. I want the protein it provides, and it’s also easy on the environment.”

The Oxford arm of the European Prospective Investigations Into Cancer (EPIC) has released a report showing that after an average of 14.9 years of follow-up, vegetarians (.88, .82-.95) and pesco-vegetarians (.88, .80-.97) each have a 12% lower risk of cancer than other meat-eaters (1).

Breaking the participants into smaller diet groups showed that vegans had a 19% lower risk of cancer:

Pesco – .88 (.80, .97)
Lacto-ovo – .89 (.83, .96)
Vegan – .81 (.66, .98)

I have updated the General Cancer section of the VeganHealth.org article, Cancer, Vegetarianism, and Diet. If you go there, you can see that the findings for vegans were similar to those in the Adventist Health Study-2 (AHS-2), the other ongoing study containing a large number of vegans.

Unlike the findings for vegans and diabetes, the statistical significance of these findings for cancer are not large. I like confidence intervals to be tighter before I get too excited about saying a vegan diet can prevent a disease. However, the consistency between EPIC-Oxford and AHS-2 should provide some assurance.

Some notes on these findings:

– The results above are not adjusted for body mass index (BMI). Adjusting for BMI slightly changed the findings for vegetarians (.90, .93-.96) and for vegans (.82, .68-1.00).

– The previous report from EPIC-Oxford had followed participants through 2005 while this current report followed them through 2010. In the intervening years, cancers increased 50%.

– Diets were assessed at baseline and after 5 years; 88% of the participants remained in their original diet category.

– No single specific cancer type could explain the differences between the diet groups; to date there has been very little consistency found between the various cancers (such as colorectal) and diet group.

Reference

1. Key TJ, Appleby PN, Crowe FL, Bradbury KE, Schmidt JA, Travis RC. Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr. 2014 Jun 4. | link

Nutrition-wise, I have been working on a resource on zinc for the Vegetarian Nutrition Dietetic Practice Group.

The only new info from that research that I had not been considering before is that people who eat a lot of soy and who take calcium supplements might have higher zinc needs. Since I fall into both those categories, I’m wondering if that’s why I seem to benefit so much from zinc. I’m happy to report that I still have not gotten more than the mildest and shortest of colds since starting zinc supplements a number of years ago.

Many links I’ve wanted to share with readers have been building up and so I’m going to knock them all out in one post right here.

Regarding the report suggesting saturated fat intake has no bearing on heart disease (see Saturated Fats in the News), Dr. Rose Marie Robertson of the American Heart Association wrote a response worth sharing: Chief Science Officer ‘sets record straight’ about diet, science, AHA.

Examine.com is a website with a panel of health writers who research a wide array of nutrition supplements and other topics. They appear to do an excellent job of assessing the research. Along with the Linus Pauling Institute at Oregon State University and the Office of Dietary Supplements, I can see Examine.com as being one of my go-to sites for seeing what research is out there.

Speaking of go-to sites, Dr. Michael Greger of NutritionFacts.org has just released Latest in Clinical Nutrition: Volume 19.

On March 10, the Washington Post ran an article (originally appearing in NewScientist) suggesting that many species of invertebrates feel pain: Do lobsters and other invertebrates feel pain? To summarize the article: octopi, squid, lobsters, crabs, and shrimp: yes. Insects: no.

Speaking of invertebrates and pain, there is a movement among some animal protectionists to promote bivalveganism. See The Ethical Case for Eating Oysters and Mussels – Part 2 at Sentientist. The author, Diana Fleischman, argues that bivalveganism can solve many of the nutrition dilemmas posed by vegan diets such as B12, iron, omega-3s, and zinc. It does seem like a decent solution for people who find it hard to thrive on vegan diets.

A report from Adventist Health Study-2 was recently released examining the association between soy intake (measured as isoflavones) and childlessness (1).

The authors write:

“The results suggest that when the isoflavone intake exceeds approximately 40 mg per day, the overall lifetime risk of never becoming pregnant increased by 13% and that of ever giving birth to a live child was reduced by approximately 3%. The associations were consistently found to be stronger in women who reported having had difficulties in becoming pregnant (1 straight year or more without success to become pregnant).”

40 mg of isoflavones per day is the equivalent of about 2 servings of soy per day.

There are some reasons not to conclude that soy causes childlessness:

• The author’s stated that, “One major limitation in our study is that we are not able to distinguish with certainty between involuntary and voluntary childlessness.”

• The finding for never becoming pregnant was 1.13 (1.02, 1.26) for women eating 40 mg of isoflavones per day compared to those eating only 10 mg. This is barely statistically significant.

• It was a cross-sectional study with relatively weak findings. Cross-sectional studies can indicate what should be studied prospectively and in clinical trials, but cannot prove causation.

• The researchers did a lot of testing with many different models, the results of which didn’t always agree. The authors stated in their discussion, “[G]iven the somewhat exploratory nature of our analyses and the many statistical tests conducted, we do not believe that [an inconsistency they found] deserves much emphasis at this point.” Indeed – that could apply to their main finding.

Despite the limitations, if someone is having a hard time becoming pregnant, cutting out the soy might be something to try.

The study is linked to in the reference below and is free to the public.

I have updated the VeganHealth.org article, Soy: What’s the Harm?

References

1. Jacobsen BK, Jaceldo-Siegl K, Knutsen SF, Fan J, Oda K, Fraser GE. Soy isoflavone intake and the likelihood of ever becoming a mother: the Adventist Health Study-2. Int J Womens Health. 2014 Apr 5;6:377-84. doi: 10.2147/IJWH.S57137. eCollection 2014. | link