This is a really good site on foot pain:

When people age, their absorption of calcium is greatly reduced, to somewhere around 25%. That usually means that you are lacking calcium, and the body will try to compensate by taking calcium from the bones. I don't know your age, diet, or body weight, but heel spurs generally happen in middle-aged people who are usually overweight. If this is the case, I would suggest you take 500mg of 1 to 1 calcium/magnesium (from citrate) three times per day. It takes about a month or so to notice improvement, so you will need some "cushion" material in your shoes to act as shock absorbers. Also, drinking green juices, like parsley, cucumber, celery, cabbage etc will help. Once your calcium/magnesium in your body is balanced, the pain will stop.

Most experts recommend the following in treating osteoporosis (before it occurs):

Which lead us to the question of the day: what accelerates bone loss to such a degree? And there are several answers:

But all of the above factors pale in comparison to the problem of a high acid diet. This is the reason the incidence of osteoporosis has soared. This is the reason more and more men are now suffering. If you have not already done so, I suggest you read Chapter 13 of Lessons from the Miracle Doctors (you can download a free copy at www.jonbarron.org/books.php> ) to better understand how a high acid diet (meat, fish, poultry, eggs, dairy, cooked grains, and refined sugars) leeches calcium from the body. The brief explanation is that when you consume a high acid diet, your body is forced to use calcium from your bones to buffer the high acid content so that your blood pH remains constant and you don't die. The problem with dairy is that it actually takes more calcium to buffer its acid content then you actually receive from the dairy -- thus the high incidence of osteoporosis in countries that consume a lot of dairy. Now, do not misunderstand. I am not saying that dairy is the biggest culprit. Actually, all of the other acid foods are worse -- particularly high sugar colas. I just single out dairy because it's always identified as building strong bones, when the opposite is true.

So what is one to do? Well, first read Chapter 6 of Miracle Doctors. It lays out the ground rules for a diet that allows your body to build bone. It suggests minimizing the intake of animal foods (to less than 3 ounces a day) and the elimination of refined grains and sugars. At that point, the amount of highly absorbable calcium that you get in your diet from foods such as romaine lettuce, broccoli, sesame seeds and bok choy will be more than adequate to build strong bones.

Think about cows for a moment. (This is one of those questions that I love to use when I want to drive doctors crazy -- a hobby of mine.) How do cows grow such large, strong bones? They don't drink milk, and they don't take calcium supplements. They eat grass -- low in calcium, high in magnesium (magnesium is the basis of chlorophyll in plants). Consider the fact that the traditional Eskimo diet contains over 2,000 mg of calcium a day, but because their diet is so acidic (virtually 100% from animal sources), it produces the highest hip fracture rate in the world. The bottom line is that calcium supplementation will not save you from the consequences of a high acid forming diet.

And if you absolutely can't change to a more alkaline diet, then taking supplemental calcium (not milk) to buffer the excess acid probably makes sense. It won't repair any damage, but it will protect against some of the destruction you are inflicting on yourself.