In this episode, I answer a listener's question about whether I am worried about my phosphorus intake and whether a high phosphorus intake is ok as long as it is balanced by calcium. I describe the biochemistry and physiology of the system that regulates calcium and phosphorus, their distribution in foods, how to determine the right balance in the diet, and how to use parathyroid hormone (PTH) as a blood measurement to assess whether the dietary balance is working for an individual.
Listen on ITunes or Stitcher.
Click here to stream.
Right-click (control-click on the Mac) here and choose “save as” (“save link as” on Mac) to download.
Subscribe in your own reader using this RSS feed.
Want transcripts? Sign up for the CMJ Masterpass with this special link to get 10% off.
Before moving on to the show notes, check out my new logo above! With a very small investment I got this from 99Designs. I'm really happy with it as a low-cost replacement for what I had before and I want to thank all the people who rated and commented on the designs when I circulated the request on Facebook and Twitter.
Show Notes for Episode 9
If you want to skip around within the episode, this will help you navigate:
02:16 The listener’s question on Ca/P
02:53 Outline of the episode
05:26 Roles of calcium and phosphorus and distribution among foods
13:56 Physiological principle of need to balance calcium and phosphorus
21:18 Role of endocrine hormones in regulating calcium and phosphorus
43:24 How different foods rich in calcium and/or phosphorus affect PTH levels (different effects of phosphorus-based additives, whole grains, meats, and cheese)
52:20 My own calcium and phosphorus intakes
55:22 Weston Price's data for calcium and phosphorus intakes in pre-industrial societies
1:02:20 Potential genetic differences in the requirement for calcium and vitamin D
Relevant Links for Episode 9
These are useful resources for better understanding the regulation of the calcium-phosphorus economy:
- The Linus Pauling Institute: Phosphorus (free)
- The calcium and phosphorus chapters in Modern Nutrition in Health and Disease.
This is one of the few textbooks I was required to purchase in school
and found so useful I kept as a cherished reference. When the most
recent edition came out, I bought the Kindle version, which is
incredibly easy to navigate and take notes from compared to the
hardcover version I have in my office.
- Robert Heaney's chapter in the Feldman Vitamin D textbook, Vitamin D: Role in the Calcium and Phosphorus Economies (behind a paywall but should be accessible through a library)
- Raposo et al., A mathematical model of calcium and phosphorus metabolism in two forms of hyperparathyroidism. The full text is available on researchgate.net.
These are the studies I talked about towards the end:
- Acute effects of different phosphorus sources on calcium and bone metabolism in young women: a whole-foods approach. The full text is available free on researchgate.net.
- Habitual high phosphorus intakes and foods with phosphate additives negatively affect serum parathyroid hormone concentration: a cross-sectional study on healthy premenopausal women. The full text is available free on researchgate.net.
- One of Jane Kerstetter's studies showing meat enhances calcium bioavailability. (free full text)
If you know of better or contradictory studies please post them in the comments. Have any personal experiences with balancing calcium and phosphorus or using PTH to help interpret your health and dietary balance? Please share!