For those of you with infants or thinking about infants, it could be a good resource not only for your own information, but to share with family, friends, doctors, and alternative medicine practitioners.
I just read a very helpful article on kidney stones that I thought I’d pass on. (Thanks, Jeff!) It was written in 2002 but to my knowledge it is still valid. It also had some information on calcium supplements and kidney stones suggesting that calcium supplements taken with meals could reduce the risk of kidney stone formation whereas taken without meals could increase the risk (in genetically predisposed people).
I modified my calcium recommendations to reflect this, and also added a page on kidney stones to VeganHealth.org and am reproducing here:
The article, Diet and Kidney Stones, by James J. Kenney, PhD, RD, FACN is an excellent resource for treating kidney stones with diet.
A quick summary is that people with calcium-oxalate stones, the most common type, should avoid high-oxalate foods (listed in the chart in the article), limit sodium to less than 1,500 mg per day, do not take vitamin C supplements, limit animal protein, and only take calcium supplements with meals.
You should also drink plenty of fluid, according to The Mayo Clinic:
Drinking as much as 2 to 3 quarts (1.9 to 2.8 liters) a day may help flush out your urinary system. Unless your doctor tells you otherwise, drink enough fluid – mostly water – to produce clear or nearly clear urine.
I received an interesting question from a vegan who is concerned that her manganese intake on a vegan diet is 4 times the DRI of 1.8 mg for women. I thought this was going to be an easy question to answer – probably in 10 minutes or less. Seven solid hours later, I have added a new page to VeganHealth.org, Manganese. It is reproduced here:
Manganese is a mineral that is essential for humans. It is part of the antioxidant system in the mitochondria, and is also involved in metabolism, bone development, and the creation of collagen for wound healing.
Although manganese is an essential nutrient, manganese toxicity has been relatively common in places where workers are accidentally exposed to large amounts of manganese. Manganese in drinking water is the biggest concern since manganese in food is not as easily absorbed.
Manganese toxicity symptoms tend to be neurological problems. Headaches, muscle cramps, fatigue, and aggressiveness are early signs of manganese toxicity, which can then proceed into Parkinson’s disease-like symptoms such as tremors (6). People with manganese toxicity have more of a tendency to fall backwards than do those with Parkinson’s (6). Studies have been mixed on whether chelation therapy, the only therapy currently available, is successful at treating overt manganese toxicity (6).
According to the Linus Pauling Institute, “A single case of manganese toxicity was reported in a person who took large amounts of mineral supplements for years, while another case was reported as a result of a person taking a Chinese herbal supplement. Manganese toxicity resulting from foods alone has not been reported in humans, even though certain vegetarian diets could provide up to 20 mg/day of manganese.”
The DRI for manganese if 1.8 mg for adult women and 2.3 mg for men. One study has measured the manganese intakes in vegans and it found an average intake of 4.1 mg for women and 5.6 mg for men (not including supplements) (1), though some vegans get much higher amounts. The upper tolerable limit for adults is 11 mg/day, although this level is considered “very conservative” by the Linus Pauling Institute.
Despite the fact that overt manganese toxicity from food rarely occurs, iron deficiency has been shown to increase the risk of manganese accumulation in the brain (6). Because iron and manganese share similar absorption mechanisms, iron deficiency can increase manganese intake (from the body trying to increase iron absorption but getting manganese instead) and high manganese intakes can depress iron absorption (3, 4). A study in miners whose drinking water was contaminated with manganese showed that manganese toxicity decreased iron status which returned to normal after the manganese was minimized in their environment (2).
People with liver damage are also at risk for manganese deficiency (6).
Manganese absorption is very low, from 1 to 5% (4). The phytic acid in a soy formula was shown to cut manganese absorption in half (from 1.6 to .7%) in adults (5). Phytic acid has a similar effect on iron absorption, but vitamin C can overcome phytic acid’s effect on iron, whereas it does not do so for manganese (5).
From this research, it seems possible that long-term iron deficiency (not necessarily anemia, but low iron stores) could increase manganese absorption on a vegan diet high enough to cause problems, though I have not heard of any long term vegans getting Parkinson’s-like symptoms or manganese toxicity.
Vegans with iron deficiency should make sure they eat vitamin C at meals so that iron is absorbed instead of manganese. Including some soy with meals for phytic acid might also be a good idea for such people.
References
1. Haddad EH, Berk LS, Kettering JD, Hubbard RW, Peters WR. Dietary intake and biochemical, hematologic, and immune status of vegans compared with nonvegetarians. Am J Clin Nutr. 1999 Sep;70(3 Suppl):586S-593S. | link
2. Boojar MM, Goodarzi F, Basedaghat MA. Long-term follow-up of workplace and well water manganese effects on iron status indexes in manganese miners. Arch Environ Health. 2002 Nov-Dec;57(6):519-28. (Abstract) | link
3. Kim Y, Lee BK. Iron deficiency increases blood manganese level in the Korean general population according to KNHANES 2008. Neurotoxicology. 2011 Mar;32(2):247-54. doi: 10.1016/j.neuro.2010.12.006. Epub 2010 Dec 21. | link
4. Finley JW. Manganese absorption and retention by young women is associated with serum ferritin concentration. Am J Clin Nutr. 1999 Jul;70(1):37-43. | link
5. Davidsson L, Almgren A, Juillerat MA, Hurrell RF. Manganese absorption in humans: the effect of phytic acid and ascorbic acid in soy formula. Am J Clin Nutr. 1995 Nov;62(5):984-7. | link
6. Aschner M, Erikson KM, Herrero Hernández E, Tjalkens R. Manganese and its role in Parkinson’s disease: from transport to neuropathology. Neuromolecular Med. 2009;11(4):252-66. doi: 10.1007/s12017-009-8083-0. Epub . Review. Erratum in: Neuromolecular Med. 2009;11(4):267. | link
If you’d like to hear an interview with me on Our Hen House about the ex-vegan phenomena, please click here.
I would like to thank Jasmin Singer and Mariann Sullivan for having me on to discuss this important topic that is not often addressed by vegan advocates.
I was urged by my most wonderful sister-in-law, an avid user of PeaCounter.com, to remind my readers of its existence. It is the website I created for diet analysis, but has many features:
• Look up the nutrient amounts as listed by the USDA Nutrient Database for specific foods.
• Look up the Dietary Reference Intake (DRI) for a given nutrient.
• Calculate caloric requirements, physical activity level, and body mass index (BMI).
• Convert measurements for height, weight, vitamin D, cholesterol, vitamin B12, energy, ideal body weight, BMI.
• Create a list of foods eaten in one day and compare nutrient amounts to daily recommendations.
• Create up to 10 free meal plans per user account.
I have never watched the Dr. Oz show, but two days ago I got a phone call from my mother saying that Dr. Oz was telling people that processed soy can mess up your hormones.
Nerdles.com provides a run down on the show that includes:
“Now the #1 thing to avoid to keep your hormones in balance is processed soy. Processed soy is stripped of all the healthy omega-3s, fiber, and are ultimately left with carbs and soy protein isolate. Inside soy protein isolate, you’re finally left with estrogen and high-levels of this will interrupt your cycle….The gold standards of soy are miso, natto, and tempeh – get these into your diet instead for healthy hormone levels.”
But processed soy does not contain more isoflavones (the “soy estrogens”) per serving than unprocessed soy, so this doesn’t make much sense. Processing soy protein concentrates the protein, not the isoflavones.
And on Dr. Oz’s website, in the article, 4-Week Cyclical Hormonal Health Plan, they bring out the old Weston Price Foundation talking points, “Traditionally, Asian cultures consume no more than two teaspoons of fermented soy a day, which has been shown to be health-promoting, while more than that quantity becomes problematic.”
The idea that Asians limit their soy to two teaspoons a day, and that it is all fermented, is not backed up by the research as reviewed in my article, Soy: What’s the Harm? – Asian Intakes. By the way, two teaspoons of soy is only 1/12 of a typical 1/2 cup serving of tempeh – not even a serving per week.
Nor is there any evidence that more than two teaspoons a day is problematic. The entire article, Soy: What’s the Harm? is a discussion of how much soy is safe (or you can see the much abridged version, Response to Not Soy Fast).
Since I have not reviewed the large amount of research on soy and menstrual cycles in any rigorous way, I asked Dr. Mark Messina, one of the world’s leading soy experts, to comment on the statement that soy will interrupt your menstrual cycle and he said:
“Soyfoods and the phytoestrogens in soy have relatively minor effects on reproductive hormone levels in women. There is evidence indicating that soy may increase the length of the menstrual cycle by approximately one day. However, when only high-quality studies are considered, the effect of soy is no longer statistically significant. Whether a possible effect of soy on menstrual cycle length has clinical implications is unclear although longer cycles are associated with a lower risk of breast cancer.”
In addition to the information on soy, that entire article, 4-Week Cyclical Hormonal Health Plan, sounds pretty far-fetched.
Because food allergies can throw a big wrench into trying to be vegan, I thought I’d pass on this article from Today about a doctor who has been desensitizing children to their severe reactions by giving them small doses of the allergenic food.
If you have severe allergies, please do not try this yourself without medical supervision!
This is an abridged version of Calcium and Vitamin D, which includes references and more details on just about every paragraph below.
Calcium
Americans are regularly being urged to consume more calcium in order to prevent osteoporosis. It is practically impossible to meet the recommendations without large amounts of cows’ milk, calcium-fortified foods, or supplements.
Because vegans do not eat dairy products, without fortified foods or supplements their calcium intakes tend to be low (about 400-600 mg per day compared to the U.S. recommended intake of 1,000 mg per day).
Traditionally, the vegan community has responded to this by saying osteoporosis is a disease of calcium loss from the bones, not a lack of calcium in the diet. This was based on two ideas.
The first idea is that ecological studies have shown that the countries with the highest intake of dairy products (northern Europe and the USA) have higher rates of hip fractures than do Asian and African countries where much less milk is consumed. This in turn, can be explained by the second idea, which is that studies show that after ingesting animal protein, people urinate large amounts of calcium.
Therefore, the thinking goes, calcium intake isn’t important for preventing osteoporosis and vegans are protected due to the lack of animal protein in their diets.
Unfortunately, there is a lot of evidence to suggest that this is not correct. It turns out that hip fractures are more indicative of the risk of falling than of osteoporosis in some countries, with a recent study from Hong Kong showing that while men and women in Hong Kong had lower rates of hip fractures, they had higher rates of vertebral factures, and the women had higher rates of osteoporosis than Caucasian women.
As for protein leaching calcium from bones into the urine – it’s a lot more complicated than that. The studies that showed calcium to be urinated out were done using protein isolates whereas eating protein from whole foods does not result in a calcium imbalance. Population studies and clinical trials show that protein, including animal protein, does not have a negative effect on bones (more details here).
So where does that leave vegans?
Vegans’ bone mineral density, a measure of osteoporosis, has been shown in many studies to be slightly lower than non-vegans. More importantly, the one study on Western vegans measuring fracture rates over time found that vegans in the group who got less than 525 mg of calcium per day had a higher fracture rate than vegans in the group getting more than 525 mg. The vegans in the lower calcium group also had higher fracture rates than the meat-eaters and lacto-ovo vegetarians.
Although it is possible to meet the calcium recommendations by eating greens alone, the average vegan probably will not meet recommendations without drinking a glass of fortified drink each day, eating calcium-set tofu, or taking a 250 – 300 mg supplement (in addition to eating an otherwise balanced diet).
The greens highest in absorbable calcium are kale, mustard greens, bok choy, turnip greens, collards, and watercress (more info). In addition to calcium, greens also contain vitamin K, potassium, and magnesium, which also contribute to better bone health.
While spinach, Swiss chard, and beet greens are high in calcium, it is not well absorbed due to their also high content of oxalates, which bind calcium and prevent absorption from the digestive tract.
Research is mixed about whether calcium intakes above 1,400 mg per day can put people at risk for chronic disease. If you take a calcium supplement, it’s best not to go overboard. Most vegans taking 250-300 mg per day would not come close to 1,400 mg.
Vitamin D
Vitamin D is also important for bones, as it can increase calcium absorption when the body signals that it needs calcium. Research has shown that in populations with calcium intakes similar to omnivores in the United States, vitamin D is more important than calcium for preventing osteoporosis.
In recent years, vitamin D has also been linked to many other diseases and some researchers have suggested that the recommended vitamin D levels are too low. However, the Institute of Medicine has reviewed the research and concluded that is not the case. The controversy has resulted in many people thinking they are deficient in vitamin D when they are not.
The only significant, natural, dietary sources of vitamin D are fatty fish, eggs (if chickens have been fed vitamin D), and mushrooms (if treated with UV rays). Most Americans get their dietary vitamin D through fortified milk and fortified margarine. The vegan diet contains little, if any, vitamin D without fortified foods or supplements. On average, vegans’ vitamin D levels are adequate, but somewhat lower than non-vegans.
Most people get a significant amount of their vitamin D from the action of UV rays on their skin. While the body can store vitamin D made in the sunnier months for use during less sunny times, this does not work for everyone. In fact, some people, even those living in sunny climates, develop extremely low levels of vitamin D. This can manifest itself through fatigue and bone pain.
If your arms and face (or the equivalent amount of skin or more) is exposed to the following amounts of midday sun (10 am to 2 pm), without sunscreen, on a day when sunburn is possible (i.e., not winter or cloudy), then you should not need any dietary vitamin D that day:
On all other days, people older than one year should get 600 to 1,000 IU of vitamin D.
Due to skin cancer concerns, some dermatologists recommend getting all your vitamin D from supplements rather than the sun. The amounts of sun above for light and dark-skinned people should be safe, but I have not seen research on how much sun is safe for elderly people and recommend talking to your doctor about how to get vitamin D if you believe you are at risk for skin cancer.
600 to 1,000 IU of vitamin D is only available in supplemental form or specially treated mushrooms.
There are two forms of supplemental vitamin D: D2 and D3. Vitamin D2 is always vegan, made from exposing fungi to UV rays. Vitamin D3 normally comes from fish oil or sheep’s wool, but there is a vegan version made by Vitashine.
A great deal of research has been conducted on vitamin D2 and D3. Vitamin D2 is effective at increasing bone mineral density (when given to people who are deficient). Vitamin D2 can also increase vitamin D levels temporarily, but is not as effective as vitamin D3 at keeping vitamin D levels raised when taken only weekly. If you take vitamin D on a regular basis, D2 should be fine, whereas if you are only going to take it sporadically, without getting sun in the interim, or find that your vitamin D levels will not increase on D2, then you should opt for D3.
If you are trying to raise your vitamin D levels with D2, make sure the laboratory can detect vitamin D2, and not just vitamin D3. Also make sure that you are not trying to raise your levels beyond what the Institute of Medicine says is adequate (50 nmol/l or 20 ng/ml) as there’s no sense in worrying if you cannot seem to get your vitamin D levels twice as high as necessary!
(Thank you to everyone who donated and used the Amazon links over the weekend! And especially to O.P. from the Southern hemisphere whose email address wasn’t working.)
I have come across another recent report on calcium supplements. This time, instead of correlating calcium intake with rates of disease, the calcification of arteries was studied (1).
Researchers in the Framingham Study measured calcium intakes and then followed participants for four years at which time they measured the amount of calcification of their arteries. They found no correlation or trends with calcium intake and calcification of the arteries in amounts up to about 3,000 mg per day in either men or women. Ditto for calcium supplements of 500 mg per day or more compared to 0 or 1-500 mg per day.
The authors of the study note one other study looking at calcification of the arteries (2) which found no association in the prospective arm, though did find a cross-sectional correlation at baseline.
One can hope that more studies will not come out to contradict these findings!
References
1. Samelson EJ, Booth SL, Fox CS, Tucker KL, Wang TJ, Hoffmann U, Cupples LA, O’Donnell CJ, Kiel DP. Calcium intake is not associated with increased coronary artery calcification: the Framingham Study. Am J Clin Nutr. 2012 Dec;96(6):1274-80. | link
2. Wang TK, Bolland MJ, van Pelt NC, Horne AM, Mason BH, Ames RW, Grey AB, Ruygrok PN, Gamble GD, Reid IR. Relationships between vascular calcification, calcium metabolism, bone density, and fractures. J Bone Miner Res. 2010 Dec;25(12):2777-85. doi: 10.1002/jbmr.183. Epub 2010 Jul 16. Erratum in: J Bone Miner Res. 2011 Feb;26(2):439. (Abstract) | link
