Many patients assume that they are forming calcium stones and should therefore limit their calcium intake. That assumption could not be more wrong. Low calcium diet won’t stop your stones and may even increase your risk. Lets not forget that our bones are in desperate need of calcium to avoid osteopenia and osteoporosis.
But, many of the best foods for calcium are also high in sodium, and sodium raises urine calcium loss and stone risk.
How Much Calcium do We Need?
The National Institutes of Health tells us age matters. Nineteen to fifty year old male or female need 1,000 mg of calcium a day. Fifty one to seventy year olds need 1,000 mg for males and 1,200 mg for females. Those above seventy one need 1,200 mg, both sexes.
We all know that much of our calcium comes from diary products. But did you know that dairy products are very high in sodium?
When we eat a high calcium food that is also high in sodium the sodium can undo the benefits of the calcium by raising urine calcium losses. This is especially true for stone formers with idiopathic hypercalciuria whose urine calcium is much more sensitive to sodium than in normal people.
So we need to search for dairy products that are lower in sodium than usual.
We also have to find what else there is because not everyone can tolerate dairy products. This means fruits and vegetables, and they may contain oxalate.
How to Read Food Labels for Calcium
All food labels are based on a 2000 calorie per day diet. Calcium is given to us in the form of a percentage.
How do we figure out how much we are getting per serving?
Take a look at the featured picture. It shows Friendship Dairy cottage cheese no salt added.
This is a great product for high calcium and low salt. On the label it tells us that per serving you will receive 10% of your daily value for calcium.
How do we convert this to milligrams?
Since we know that every food label is based upon a 2000 calorie per day diet, and gives the percent of the recommended 1,000 mg of calcium for that diet, we can just put a 0 at the end of the percent. So 10 percent is 100 mg of calcium. In this case a serving size is half of a cup. Eat more or less and the calcium from the product will vary.
We are going to continue with the example of the cottage cheese
The low salt version of Friendship Cottage Cheese has only 60 mg of sodium per serving. The regular Friendship cottage cheese contains 260 mg/serving. This is a great sodium savings in that the ideal intake of sodium is only 1,500 mg daily.
As a contrast take a look at this product.
The label, which does not show, says a serving contains 15% of daily requirement which is 150 mg of calcium. But the sodium in that serving is 290 mg!
The Trouble with Food Labels
These Friendship and Breakstone cottage cheese products are two excellent examples of how difficult it is to distinguish between really low sodium and rather high sodium products.
The 30% less sodium label is correct, but it is 30% less than a lot of sodium. The Friendship label tells you there is no salt added, which is also true.
But the actual sodium amounts are what you want to look at. They have to be accurate by law and they are.
You have to notice the small subtleties in all food labelling. It is definitely worth the time if you want to keep sodium low while getting adequate calcium.
How to Shop for Low Sodium Dairy Products
We have to become experts at reading food labels. Don’t pay mind to the front of the package. The nutrition label is the only thing you need to look at. You want the highest calcium for the lowest sodium, and the only way to get it is by looking at the label. Sometimes this may require you to look at several brands. You may have to stop using your favorite brand.
In the beginning of this process it may seem this is a daunting task.
But before long you will become quite efficient and even a food label expert.
No Food Label?
Many of you will shop at the deli counter or prepared food section, or eat in a restaurant. You will just have to remember that certain dairy products have a lot of salt – like cheese – and find the low sodium alternatives. When you are asking the deli counter person to cut you some cheese or the waiter to bring you a fancy cheese plate you have to ask for the low sodium varieties if there are any.
What if You Can’t or Won’t Eat Dairy Products
If you won’t maybe you should take a look at our list and reconsider. The list is ordered by how much calcium is in a serving. Dairy products win by a big margin. So if you possibly can use them, use them.
The remaining options are fruits, vegetables, fish, and supplemented foods. We have consulted the usda data laboratory charts for calcium and sodium, and our own oxalate lists to give you what we can find with modest oxalate and a high calcium per sodium ratio. We have redacted from the immense usda lists our list of the best calcium to sodium bargains adjusting for oxalate from our oxalate lists.
The list is what we think will be most useful to you. Below we highlight a few foods in each category that we specially like.
Fruits and Juices
Fruits have very little sodium when raw and fresh, so it is all about their calcium content.
The most calcium in this category will be found in one cup of calcium fortified orange juice – 366 mg. Calcium supplemented grapefruit juice gives 350 mg of calcium in 8 ounces. The oxalate in grapefruit is modest and will fit into most diets. Apple juice fortified with calcium has little oxalate and is a good choice. We emphasize that these are calcium supplemented juices, otherwise they will not do.
Some useful foods have too little calcium to make our list but are good, Pineapple juice, 6 ounces gives 84 mg of calcium. Plums and apricots are very low in oxalate and a cup gives about 70 mg of calcium. Blueberries and pears are low in oxalate and give about 60 mg for a cup. Peaches give about 50 mg of calcium/cup.
Fish and Seafood
Sardines, no salt added, have about 150 mg of calcium and 50 mg of sodium in a serving. Three ounces of canned salmon provides 212 mg of calcium and 64 mg of sodium. Most other fish, even fresh, have about 80 mg of sodium for every 120 mg of calcium, which is not a great ratio. Crustacea have very high sodium levels even when fresh.
From the list, here are a few highlights.
Kale, frozen, boiled, and drained without salt has 179 mg of calcium, 20 mg of sodium and little oxalate – a great bargain. Mustard greens, frozen, are low in oxalate and have 152 mg of calcium with 38 mg of sodium. Chinese cabbage (bok choy) has 158 mg of calcium and 58 mg sodium in 1 cup, and very little oxalate.
Several foods are too low to make the list but are tasty and can be used. Winter squash gives 80 mg calcium and 8 mg sodium in one cup. Raw onions have little oxalate but 72 mg of calcium and 8 mg of sodium in a cup. Cowpeas, if you find them, also known as black eye peas, have 184 mg of calcium, and 27 mg sodium in a cup.
So Now What?
You may not like what I am about to say but that’s not going to stop me from saying it. For people who choose to avoid dairy products by choice or because of lactose intolerance or food allergy, it is difficult to get enough calcium into the diet without an excess of sodium and in the case of fruits and vegetables too much oxalate. There is one usable alternative milk and yogurt product: coconut. Soy and almonds are too high in oxalate.
That leaves supplements. We have already mentioned calcium supplemented juices. Pill supplements can be used – check with your physicians – but only with substantial meals. Taken without food they can raise urine calcium a lot and it is not clear that bone cells will use the calcium. So used improperly supplements can increase stone risk. With meals, supplements can and do lower urine oxalate.