'Where do you get your calcium?' Probably the second most commonly-asked question of the raw vegan (after 'Where do you get your protein?') and sometimes followed (especially if one is a woman of a certain age) with 'Aren't you worried about osteoporosis?' And those who ask are concerned because they've understood all their lives that we 'need' dairy for calcium.
Now please remember I'm neither doctor nor dietician etc etc, so please take everything I say with a pinch of salt. (On the other hand...don't do that.) I've drawn my conclusions simply from information gleaned from trawling the internet over the past year. But, this does suggest that raw vegans need not worry about calcium intake, or indeed osteoporosis (brittle bones). And, if you're a man, please do keep reading, as osteoporosis isn't confined to women, and...you do have teeth (I hope).
Why do we need calcium?
Altogether now... 'for healthy bones and teeth'! (and we need it for quite a few other things as well, eg proper blood clotting, muscle functioning, hormone activation, etc, and it's essential in the maintenance of the acid-alkaline balance.).
How much do we need each day?
UK Dept of Health recommends 700 mg (more when pregnant and breast-feeding)
Where can we obtain calcium on a raw vegan diet?
Two of the best, and widely-available, sources:
Dark green leaves (eg spinach/kale) (2 cups) 200 mg
Nuts (eg almonds, hazelnuts)(100g) 200 mg
- Sea vegetables (100g) 200 mg
- Watercress (100g) 150 mg
- Lettuce (2 cups) 80 mg
- Parsley (1 cup) 80 mg
- Broccoli (1 cup) 80 mg
- Figs (4 medium) 72 mg
- Sesame seeds (50g) 70 mg (buy whole-calcium reduced by 90% when de-hulled.)
- Olives (100g) 60 mg
- Oranges (1) 50 mg (note the calcium is in the pulp and pith)
And calcium is also found in many other plant foods.
Note that natural sunlight is vital to calcium absorption. So, if the sun's shining outside right now, you know what to do when you've read this article! We can store Vitamin D for months. Were there any days in the summer where the sun was shining outside and you were spending (unnecessary) time on the computer? As well as Vitamin D, our bodies need Vitamins A, C, magnesium, phosphorus and various amino-acids to absorb calcium, so the healthier the diet overall, the more calcium will be absorbed.
(You may have heard that foods high in oxalic acid can inhibit calcium absorption, and that spinach is one of these. However, my research indicates that this would only be a problem if we have vast quantities of the tougher, mature leaves rather than the young leaves most of us eat. Chard and beet greens are also high in oxalic acid. I find Swiss Chard burns my throat and guess this is the acid, so avoid it for that reason. Beetroot itself gives me this sensation occasionally. The young spinach leaves I buy (and grow) don't when I eat them in leaf form, but occasionally do in smoothies. Basically, let your taste buds guide you.
Unnaturally large amounts of fibre can impair the body's ability to absorb calcium, but the key word here is 'unnaturally'. Bran, for example, is a fractured food - the fibre having been removed from the whole food, and bran can inhibit the absorption of calcium. Fibre that is ingested within whole fruit and veg should not have adverse effects.)
Salt can also have an adverse effect on calcium absorption. The World Health Organisation, in 'Vitamin and Mineral Requirements in Human Nutrition' tell us that sodium competes with calcium in the body. The more sodium, the less calcium is absorbed and that 'salt restriction is likely to lower our calcium requirements.'
'But I only eat one or two of those foods each day. How am I going to reach 700 mg?'
(1) The allowances are liberal to start with. They've been set high deliberately to allow for 'calcium loss' (and one of the causes of this is meat-eating! More later.)
(2) They are based on what scientists believe the average person needs. The average person is unhealthy and eating cooked food - the average person is malnourished. There is plenty of evidence to suggest that healthy individuals eating raw, whole foods are thriving on a fraction of the allowances recommended for conventional eaters.
(3) According to the Vegan Society, vegans are not generally calcium-deficient and they do not appear to have a higher rate of osteoporosis than the general population (and more on that later).
(4) Chinese living in rural areas (unlike those living in towns, where the diet is more westernise) have a very low calcium intake and osteoporosis is rare.
Taking the above into account, I think it's fair to say that the raw vegan is going to need significantly less than 700 mg a day. The average intake of those rural Chinese is less than 200 mg a day (dairy consumption is very low) and they appear to do just fine on such a 'low' intake.
Vegans, calcium and bones...
And vegans don't appear to have bone problems...
Do vegans suffer from more 'calcium deficiency' than the general population? No, according to the Vegan Society.
Do vegans have lighter bone mass than the average? Yes! (According to researchers at the Washington University School of Medicine).
But did these light-bone-mass vegans have osteoporosis? No! (same study). And, what's more, the study reported that people on a raw vegetarian diet (this was defined as 'only plant-derived foods') not only have no higher incidence of osteoporisis than the average, but they have higher levels of Vitamin D, which is necessary for calcium absorption (perhaps because raw vegetarians/vegans, taking more care with their health generally, spend time outdoors a little more than the average.)
And new research appears to indicate that high bone density early in life is associated with osteoporosis, and high calcium intake is associated with bone-fracture in old age (see Wikipedia 'raw foodism' page - the footnotes will take you to the research source). Hmm...not what we've been led to believe, is it?!
So who's likely to have on osteoporosis problem?
Ironically, those eating animal foods...
Studies in recent years have suggested that those eating meat and dairy products (who, according to Joseph Pizzorno ND 'Total Wellness' only ingest 40-50% of the RDA anyway) will then be losing calcium from their bones through eating those very foods!
This is because: for healthy bones we need a 1.5:1 ratio of calcium to phosphorus in our diets. Problem is...meat contains 10 to 20 times as much phosphorus as calcium, and, overall, those on a standard diet including meat consume roughly 2 to 4 times as much phosphorus as calcium (University of Maryland Medical Center). When there is more phosphorus than calcium in the system, the body leeches calcium from the bones. Result - some body functions protected, but at the expense of teeth and bones.
Meat and fish have an acidic effect on the body. And, as above, our bodies try to correct this by taking (alkaline) calcium from the bones. Eskimos eat a lot of fish; they also have a high rate of osteoporosis. After the age of 40, Eskimos of both sexes have a 10-15% greater bone loss than the US average.
There is also too much phosphorus in cows' milk. Harvard School of Public Health compared post-menopausal women drinking three glasses of milk a day with a control group who didn't. The milk group lost bone at twice the rate of the control group. Osteoporosis is more common in Westernised countries where consumption of dairy is high.
We're told to eat dairy for calcium, but although it may contain calcium, it's difficult for our bodies to get it. The calcium is wrapped up in a sticky protein called casein, and the only thing able to split casein is rennet. Humans only produce this when they are babies. The problem is exacerbated when milk is pasteurised. The complex organic salts of calcium and magnesium, in conjunction with carbon and phosphorus, are decomposed by heat, resulting in the precipitation of insoluble calcium phosphate salts. These inorganic salts are not assimilable by the body.
Another problem with eating protein such as flesh or dairy is that the stomach has to work hard to break these foods down, and has to secrete significant amounts of hydrochloric acid to do so. The liver then has to neutralise that acid to prevent burning of the small intestine. The major element in the bile salts produced is...calcium. The bodies of those who consume lots of dairy (and most on the standard cooked diet do) are likely to run out of stored calcium to cope with the onslaught of all the 'concentrated protein' food and, again, leech it from the bones.
Interestingly, the American Dietetic Association in 1993 said that the daily calcium allowances recommended were increased because of the calcium losses incurred by the typically high-protein diet!
(note vegans still need to be following a healthy diet as salt, alcohol and carbonated drinks such as Coke (not applicable to raw vegans of course!) can all contribute to calcium loss).
People should be less concerned about the amount of calcium they're taking in, and more concerned about the things they're putting into their bodies that are interfering with calcium absorption, and causing their bodies to leach calcium from the bones to correct internal ph. As healthy raw vegans won't be ingesting any of those things, the raw vegan is likely to need to ingest far less calcium than a person on a standard cooked diet.
Women suffering from bone problems have traditionally been told to consume more dairy. Whilst I have explained why raising dairy could lead to a net loss of calcium, it may also raise cholesterol, clog the arteries and cause other health problems associated with high consumption of pasteurised dairy.
On 10th July, I'll be spending two hours having various tests taken and questions asked about my diet and lifestyle as part of the national Biobank project (longitudinal study of thousands of people in the UK 40+). Amongst the tests will be a bone density scan (!). I've already been warned that this test is a crude one and that a 'proper' test can reveal a quite different result, but even if the test(s) does show that I have 'low bone density' - I won't be rushing out to buy a block of Cheddar.
(EDIT 11th July 08 - my bone density result was 76 dbh/MHz, which was classed as 'good'). All my 'measurements' were good, including blood pressure of just 105/59, which is what I'd expect as a raw vegan who, even when raw vegetarian last year, ate very little dairy. Basically, my heart doesn't have to pump very hard to get the blood round, as my arteries aren't clogged. I remember reading a heart specialist say that if his patients all turned raw vegan then he wouldn't have any more work to do. ).
(EDIT Feb '10 - my blood-level calcium was tested recently. I don't have the exact figure, but the doctor informs me it is 'normal'.)