Lactose intolerance describes a digestive disorder that occurs when the body fails to produce enough of the enzyme lactase that functions to breakdown lactose---the sugar found in milk products. Those who suffer from lactose intolerance experience the symptoms of abdominal cramps, gas, bloating and diarrhea 30 minutes to 2 hours following the ingestion of milk products, according to the National Digestive Diseases Information Clearinghouse. Because milk contains so many essential vitamins and minerals, including calcium, as well as protein those who cannot drink milk must find alternative sources.
Tofu
Tofu, also known as bean curd, is produced using soy milk, a liquid beverage produced using soy beans. Heating soy milk induces it to curdle, or solidify. The curds become tofu in a method similar to the process of producing cheese from milk. The amount of water extracted from the curds determines the type of tofu produced. Tofu may be firm, firm silken or silken---the creamiest form.
Tofu naturally provides a rich source of protein. Firm tofu contains 13.4g of protein per 3-oz. serving, according to The University of Illinois Center for Soy Foods. Firm silken tofu provides 5.9g and silken tofu provides 4.1g for the same size serving. In order to extract the curds from the liquid, salt must be added. Tofu extracted using calcium sulfate provides an excellent source of calcium with four ounces providing between 200 and 330mg of calcium, according to The Vegetarian Resource Group.
Green Vegetables
Some dark, green, leafy vegetables provide an excellent source of calcium. These vegetables include kale, okra, bok choy, mustard greens, tahini and broccoli. Some green leafy vegetables, including spinach, rhubarb, chard and beet greens contain calcium but also contain oxalic acid, which inhibits the absorption of the calcium. These vegetables should therefore not be considered good sources of calcium.
Animal Proteins
Milk contains proteins classified as caseins. Most types of milk contain three to four different casein proteins that digest easily in the intestines and therefore offer a good source of amino acids that support growth and development. For lactose intolerant patients, the proteins found in milk can be replaced with proteins found in other animal products, such as meats, fish and eggs. One egg provides 6g of protein. A 6-oz. serving of salmon provides 34g of protein and the same size serving of steak provides 38g of protein.
Vegetable Proteins
Although animal products provide proteins, they also contain undesirable substances such as saturated fats. A steak delivers 44g of fat with 16 of those from saturated fat, while the salmon delivers 18g of fat, with 4g from saturated. Lentils, a type of bean, provide 18g of protein per 1 cup serving while only delivering 1g of fat. Other protein-rich vegetable sources include other beans, nuts and whole grains.
