Interview with Brenda Davis

Part 1 - Calcium Rich Foods

I have a very special guest today.  Brenda Davis is the most popular Redistered Dietitian I know of,   a leader in her field and an internationally acclaimed speaker.  She is a co-author of seven books: Becoming Raw, Becoming Vegan, Becoming Vegetarian, The Raw Food Revolution Diet, Defeating Diabetes, Dairy-free and Delicious, and an Amazon bestseller, The New Becoming Vegetarian.

Brenda's book, Becoming Vegan, encouraged me  to try the vegan diet.  It was full of practical tips, unbiased advice,  and scientifically proven facts. I  highly recommend it, especially to the parents whose teenagers set their minds on becoming vegan, elderly people, and future moms.

Today,  Brenda is answering your  questions  about foods rich in calcium.

Brenda, many people consume dairy, especially milk, to get their calcium. Is milk the best source of calcium?

We have no need for cow’s milk, or the milk of any other mammal (apart from our own mothers). It truly defies rationality to assume that any species would require milk of another species for their survival. It makes absolutely no sense. But that doesn’t mean that cow’s milk is not a rich source of calcium. All mammals’ milk has calcium, including human milk. Cow’s milk provides about 300 mg of calcium per cup.

Cow’s milk is not necessarily the best source of calcium for people. In my opinion, the best sources are kale and dark green leafy vegetables. Hundreds of years ago an average human being consumed 1500 – 2000 mg of calcium a day – without a drop of milk from other species; they got most of their calcium from wild greens.

Are there any other benefits of getting calcium from plant sources?

The benefits of getting our calcium from plants are many – first, in addition to calcium, they provide many other nutrients that people need for bone health – vitamin K, vitamin C, folic acid, magnesium, potassium and boron, for example.

• Vitamin K is very important for bone health, but is not on the radar of the average person because dairy products are not a rich source, and much of the bone health information available comes directly from the dairy industry. Vitamin K comes primarily from leafy greens.
• You also get bone-building minerals such as magnesium, potassium from plants.
• In addition, plants are low in cholesterol and saturated fats.
• They are also alkaline forming – which is another bonus for your bones. Acid-forming diets tend to cause increases in urinary excretion of calcium The body pulls calcium out of your bones to neutralize the acid that you get from animal products and many processed foods.

ARE VEGANS ACTUALLY GETTING ENOUGH CALCIUM?

The answer is that many of them don’t.

Three out of four studies found reduced bone health in vegans compared to lacto-ovo and non–vegetarians. And these studies found that most vegans are taking in half of the RDA for women, and 2/3s the RDA of men.

There is a study called "EPIC", which is a huge study comparing four dietary groups: meat eaters, fish eaters, vegetarians and vegans. The study included almost 35,000 people. The researchers calculated incident risk ratios for each group. Compared to meat eaters with a risk ratio of 1.0, fish eaters had a risk ratio of 1.01 (about the same as meat eaters), lacto-ovo vegetarians had a risk ratio of 1.0 (same as meat eaters) and vegans had a risk ratio of 1.3. That means that the vegans had about 30% more fractures than the other dietary groups. This is not good news.

However, the difference disappeared in anyone consuming more than 525 mg of calcium a day. So, to be clear, there was no difference in the bone health of vegans who ate more than 525 mg calcium per day when compared to other dietary groups (in fact, there bone health was slightly better than the fish eaters and the LOV, and about the same as the omnivores).

What happens when vegans actually meet the RDA?

We don’t really know, but my guess is that there bone health might be even better than the other dietary groups. Unfortunately, most vegans fall short: 44.5 percent of them had intakes of less than 525 mg and 76.1 percent had intakes under 700 mg.

From a personal perspective, I am considered at high risk, as my mother has osteoporosis, and I am a slim, Caucasian female. My doctor figured that my avoidance of dairy further increased my risk. As I neared the age when my mother was diagnosed, I had a bone density test. I had been vegan or near-vegan for almost 20 years at that point. I have always been careful to come close to the recommended amount of 1000 mg per day in calcium intake. My bone density was 2 -21/2 standard deviations above norm for my age.

The conclusion from research is that the higher fracture risk rates in vegans appear to be a consequence of considerably lower calcium intakes. Calcium intake is important for bone health, irrespective of dietary preferences.

So what do you recommend?

The question that often comes up is, "Do vegetarians really need that much calcium?" Basically, active vegetarians and vegans may need slightly less than recommended, but it all depends on what their diet is like. People who eat a lot of processed foods or added salt, likely need more than people who are eating a lower sodium, high vegetable diet.

I do pay attention to my calcium intake. And I also do a lot of exercise. These are both protective.

But the other big question is whether calcium in plants is bioavailable. Can we actually absorb calcium in plants?

A lot of people believe that you can only absorb calcium from milk

The truth is that you actually absorb a considerable amounts of calcium from plants. You absorb about 32-34 percent of calcium in dairy products. That compares to about 31 percent for tofu and about 20-28 percent from legumes and soy milk.

Here is the good news: you absorb about 40 to 70 percent of  calcium from dark green leafy vegetables like kale, broccoli, Chinese greens, turnip and mustard greens. You absorb close to twice as much calcium from those foods as you do from milk.

The bad news is that some greens contain oxalic acid or oxalates. Oxalate binds with calcium, greatly reducing its absorption from these foods.

You only get about 5 percent of the calcium from spinach. Beet greens and Swiss chard are also rich in oxalates, so not great calcium sources. A lot of people ask me about collard greens. Collards are somewhere in-between the greens with excellent calcium availability and those that aren’t so great. So, although we don’t have exact figures, it is likely somewhere around 20 percent or so. This doesn’t make spinach, beet greens and Swiss chard "bad greens". There is no such thing as bad greens unless they are poisonous. Greens are the most nutrient dense foods on the planet. Spinach may not be the best source of calcium, but it is an excellent source of folic acid! Just don’t rely on it as a calcium source.

What factors negatively affect calcium absorption?

Factors reducing absorption are: not getting enough Vitamin D, and getting too much oxalate and/or phytate. Sources of phytate are unsprouted cereal grains. A wonderful way to reduce phytase is by sprouting. Wheat bran is the most concentrated source of phytates – it inhibits the absorption of all kinds of minerals. So, while we do want to eat whole grains, we don’t want to sprinkle bran on everything. Also, sodium increases excretion of urinary calcium.

Many people think protein is really bad for bones, and we are beginning to understand why that is not the case. You need protein to build bones. It is true that excess protein induces urinary calcium losses, but it also increases osteoblast formation, so helps to build bones. In the end, it seems to help more than it hurts. However, people that eat a ton of meat (Atkins-style diets) may eat too much and the acid load can cause bone deterioration.

There’s one important study that shows that vegetarians who consume more plant protein have stronger bones than vegetarians with lower protein intakes.

To summarize, what should one do to get enough calcium?

• Load up on vegetables and fruits;
• Keep sodium intake low
• Get sufficient protein from plants – especially legumes, nuts and seeds.
• Also, get plenty of weight-bearing exercise. Ideally, about 60 minutes a day on 5 -6 days in a week.

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Read Brenda's thoughts on B12 Foods and B12 deficiency symptoms: Vitamin B12 Foods: Interview With Brenda Davis, RD

Visit Brenda's website, for in-depth information about calcium rich foods and other important nutrients.

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