The findings of some but not all studies suggest that consumption of soft drinks may increase the risk of forming a kidney stone. The phosphoric acid found in these beverages is thought to affect calcium metabolism in ways that might increase kidney stone recurrence risk.
Nutritional supplements that may be helpful
IP-6 (inositol hexaphosphate, also called phytic acid) reduces urinary calcium levels and may reduce the risk of forming a kidney stone. In one trial, 120 mg per day of IP-6 for 15 days significantly reduced the formation of calcium oxalate crystals in the urine of people with a history of kidney stone formation.
In the past, doctors have sometimes recommended that people with a history of kidney stones restrict calcium intake because a higher calcium intake increases the amount of calcium in urine. However, calcium (from supplements or food) binds to oxalate in the gut before either can be absorbed, thus interfering with the absorption of oxalate. When oxalate is not absorbed, it cannot be excreted in urine. The resulting decrease in urinary oxalate actually reduces the risk of stone formation, and the reduction in urinary oxalate appears to outweigh the increase in urinary calcium. In clinical studies, people who consumed more calcium in the diet were reported to have a lower risk of forming kidney stones than people who consume less calcium.
However, while dietary calcium has been linked to reduction in the risk of forming stones, calcium supplements have been associated with an increased risk in a large study of American nurses. The researchers who conducted this trial speculate that the difference in effects between dietary and supplemental calcium resulted from differences in timing of calcium consumption. Dietary calcium is eaten with food, and so it can then block absorption of oxalates that may be present at the same meal. In the study of American nurses, however, most supplemental calcium was consumed apart from food. Calcium taken without food will increase urinary calcium, thus increasing the risk of forming stones; but calcium taken without food cannot reduce the absorption of oxalate from food consumed at a different time. For this reason, these researchers speculate that calcium supplements were linked to increased risk because they were taken between meals. Thus, calcium supplements may be beneficial for many stone formers, as dietary calcium appears to be, but only if taken with meals.
When doctors recommend calcium supplements to stone formers, they often suggest 800 mg per day in the form of calcium citrate or calcium citrate malate, taken with meals. Citrate helps reduce the risk of forming a stone (see “Dietary changes that may be helpful” above). Calcium citrate has been shown to increase urinary citrate in stone formers, which may act as protection against an increase in urinary calcium resulting from absorption of calcium from the supplement.
Despite the fact that calcium supplementation taken with meals may be helpful for some, people with a history of kidney stone formation should not take calcium supplements without the supervision of a healthcare professional. Although the increase in urinary calcium caused by calcium supplements can be mild or even temporary, some stone formers show a potentially dangerous increase in urinary calcium following calcium supplementation; this may, in turn, increase the risk of stone formation. People who are “hyperabsorbers” of calcium should not take supplemental calcium until more is known. Using a protocol established years ago in the Journal of Urology, 24-hour urinary calcium studies conducted both with and without calcium supplementation determine which stone formers are calcium “hyperabsorbers.” Any healthcare practitioner can order this simple test.
Increased blood levels of vitamin D are found in some kidney stone formers, according to some, but not all, research. Until more is known, kidney stone formers should take vitamin D supplements only after consulting a doctor.
Both magnesium and vitamin B6 are used by the body to convert oxalate into other substances. Vitamin B6 deficiency leads to an increase in kidney stones as a result of elevated urinary oxalate. Vitamin B6 is also known to reduce elevated urinary oxalate in some stone formers who are not necessarily B6 deficient.
Years ago, the Merck Manual recommended 100–200 mg of vitamin B6 and 200 mg of magnesium per day for some kidney stone formers with elevated urinary oxalate. Most trials have shown that supplementing with magnesium and/or vitamin B6 significantly lowers the risk of forming kidney stones. Results have varied from only a slight reduction in recurrences75 to a greater than 90% decrease in recurrences.
Optimal supplemental levels of vitamin B6 and magnesium for people with kidney stones remain unknown. Some doctors advise 200–400 mg per day of magnesium. While the effective intake of vitamin B6 appears to be as low as 10–50 mg per day, certain people with elevated urinary oxalate may require much higher amounts, and therefore require medical supervision. In some cases, as much as 1,000 mg of vitamin B6 per day (a potentially toxic level) has been used successfully.
Doctors who do advocate use of magnesium for people with a history of stone formation generally suggest the use of magnesium citrate because citrate itself reduces kidney stone recurrences. As with calcium supplementation, it appears important to take magnesium with meals in order for it to reduce kidney stone risks by lowering urinary oxalate.
It has been suggested that people who form kidney stones should avoid vitamin C supplements, because vitamin C can convert into oxalate and increase urinary oxalate. Initially, these concerns were questioned because the vitamin C was converted to oxalate after urine had left the body. However, newer trials have shown that as little as 1 gram of vitamin C per day can increase urinary oxalate levels in some people, even those without a history of kidney stones. In one case report, a young man who ingested 8 grams per day of vitamin C had a dramatic increase in urinary oxalate excretion, resulting in calcium-oxalate crystal formation and blood in the urine. On the other hand, in preliminary studies performed on large populations, high intake of vitamin C was associated with no change in the risk of forming a kidney stone in women, and with a reduced risk in men. This research suggests that routine restriction of vitamin C to prevent stone formation is unwarranted. However, until more is known, people with a history of kidney stones should consult a doctor before taking large amounts (1 gram or more per day) of supplemental vitamin C.
Chondroitin sulphate may play a role in reducing the risk of kidney stone formation. One trial found 60 mg per day of glycosamionoglycans significantly lowered urinary oxalate levels in stone formers. Chondroitin sulphate is a type of glycosaminoglycan. A decrease in urinary oxalate levels should reduce the risk of stone formation.
In a double-blind trial, supplementation with 200 IU of synthetic vitamin E per day was found to reduce several risk factors for kidney stone formation in people with elevated levels of urinary oxalate.
Herbs that may be helpful
Two trials from Thailand reported that eating pumpkin seeds reduces urinary risk factors for forming kidney stones. One of those trials, which studied the effects of pumpkin seeds on indicators of the risk of stone formation in children, used 60 mg per 2.2 pounds of body weight—the equivalent of only a fraction of an ounce per day for an adult. The active constituents of pumpkin seeds responsible for this action have not been identified.
Lactose Intolerance
Lactose intolerance is the impaired ability to digest lactose (the naturally occurring sugar in milk). The enzyme lactase is needed to digest lactose, and a few children and many adults do not produce sufficient lactase to digest the milk sugar. The condition is rare in infants.
Only one-third of the population worldwide retains the ability to digest lactose into adulthood. Most adults of Asian, African, Middle Eastern, and Native American descent are lactose intolerant. In addition, half of Hispanics and about 20% of Caucasians do not produce sufficient lactase as adults.
A simple test for lactose intolerance is to drink at least two 8-ounce glasses of milk on an empty stomach and note any gastrointestinal symptoms that develop in the next four hours. The test should then be repeated using several ounces of cheese (which does not contain much lactose). If symptoms result from milk but not cheese, then the person probably has lactose intolerance. If symptoms occur with both milk and cheese, the person may be allergic to dairy products (very rarely can lactose intolerance be so severe that even eating cheese will cause symptoms). In addition to gastrointestinal problems, one study has reported a correlation in women between lactose intolerance and a higher risk of depression and PMS. However, this study is only preliminary and does not establish a cause-and-effect relationship.
What are the symptoms of lactose intolerance?
In people with lactose intolerance, consuming foods containing lactose results in intestinal cramps, gas, and diarrhoea.
Dietary changes that may be helpful
Although symptoms of lactose intolerance are triggered by the lactose in some dairy products, few lactose-intolerant people need to avoid all dairy. Dairy products have varying levels of lactose, which affects how much lactase is required for proper digestion. Milk, ice cream, and yogurt contain significant amounts of lactose—although for complex reasons yogurt often does not trigger symptoms in lactose-intolerant people. In addition, lactose-reduced milk is available in some supermarkets and may be used by lactose-intolerant people.
Many people with lactose maldigestion tolerate more lactose in experimental studies than in everyday life, in which their symptoms may result from other carbohydrates as well. Sucrose and the indigestible carbohydrates lactulose and fructooligosaccharides (FOS) have all been shown to produce symptoms in lactose-intolerant and milk- intolerant people.
Nutritional supplements that may be helpful
Supplemental sources of the enzyme lactase may be used to prevent symptoms of lactose intolerance when consuming lactose-containing dairy products. Lactase drops may be added to regular milk 24 hours before drinking to reduce lactose levels. Lactase drops, capsules, and tablets may also be taken orally, as needed, immediately before a meal that includes lactose-containing dairy products. The degree of lactose intolerance varies by individual, so a greater or lesser amount of oral lactase may be needed to eliminate symptoms of lactose intolerance. Researchers have yet to clearly determine whether lactose-intolerant people absorb less calcium. As lactose-containing foods are among the best dietary sources of calcium, alternative sources of calcium (from food or supplements) are important for lactose- intolerant people. A typical amount of supplemental calcium is 1,000 mg per day.
Lactobacillus acidophilus supplements do not appear to be effective in reducing the signs and symptoms of lactose intolerance. In a preliminary trial, people with lactose intolerance were given Lactobacillus acidophilus supplements twice daily for seven days, but failed to show any improvement in symptoms or laboratory measurements of lactose digestion.
Low Back Pain
The low back supports most of the body’s weight, and as a result, is susceptible to pain caused by injury or other problems. Over 80% of adults experience low back pain (LBP) sometime during their life. More than half will have a repeat episode.
It is often difficult to pinpoint the root of low back pain, though poor muscle tone, joint problems, and torn muscles or ligaments are common causes. A herniated or slipped disc may also cause low back pain as well as sciatica, a condition where pain travels down one or both buttocks and/or legs.
Standing or sitting for extended periods, wearing high heels, and being sedentary increase the risk of developing low back pain, as do obesity and back strain due to improper lifting. Up to half of pregnant women experience some low back pain. Long hours spent driving a car may contribute to a herniated disc. This is possibly due to the vibration caused by the car.
Many people with low back pain recover without seeing a doctor or receiving treatment. Up to 90% recuperate within three to four weeks, though recurrences are common, and chronic low back pain develops in many people. Low back pain is considered acute, or short-term, when it lasts for a few days up to many weeks. Chronic low back pain refers to any episode that lasts longer than three months.
While low back pain is rarely life threatening, it is still important to have chronic or recurring back pain assessed by a healthcare professional. Potentially serious causes include spinal tumour, infection, fracture, nerve damage, osteoporosis, arthritis, or pain caused by conditions found in internal organs such as the kidneys.
What are the symptoms of low back pain?
Low back pain may be a steady ache or a sharp, acute pain that is worse with movement.
Lifestyle changes that may be helpful
Preliminary data indicate that smoking may contribute to low back pain. One survey of over 29,000 people reported a significant association between smoking and low back pain. Smaller people (children, women, those who weigh less) are most affected. A study involving people with herniated discs found that both current and ex-smokers are at much higher risk of developing disc disease than non-smokers. Other research reveals 18% greater disc degeneration in the lower spines of smokers compared with nonsmokers. Smoking is thought to cause malnutrition of spinal discs, which in turn makes them more vulnerable to mechanical stress.
One survey reported that people who drank wine healed more quickly after disc surgery in the lower back than those who abstained. However, alcohol consumption may cause cirrhosis of the liver, cancer, high blood pressure, and alcoholism. As a result, many doctors never recommend alcohol even though moderate consumption has been linked to some health benefits. For those deciding whether light drinking might help with recovery from disc surgery, it is best to consult a doctor.
Regular exercise and proper lifting techniques help prevent low back problems from developing. Proper lifting involves keeping an object close to the body and avoiding bending forwarding, reaching, and twisting while lifting. Low back pain and disc degeneration are both more likely to develop among sedentary people than those who are physically active. However, long-term participation in some competitive sports may contribute to spinal disc degeneration.
Therapeutic exercise helps people recover from low back pain and low back surgery. Less clear are details about how this should be done for greatest benefit. In other words, the best type of exercise, frequency, duration, and timing of a program still need to be determined. One study reported therapeutic exercise significantly improved chronic low back pain compared to exercise performed at home without professional guidance. Another trial discovered that women with chronic low back pain who began supervised back strengthening exercises at a fitness centre were more consistent exercisers than those who started and continued therapeutic exercises at home. Both groups experienced significant improvement in pain. However, the supervised group experienced better long-term improvement.
While heavy lifting and other strenuous labour may contribute to low back pain, one trial found that people with sedentary jobs gained more benefit from an exercise program than those who have physically hard or moderate occupations. Motivational programs may also improve exercise consistency, which in turn decreases pain and disability. People with low back pain who wish to embark on an exercise program should first consult with a physical therapist or other practitioner skilled in this area.
Supervised bed rest, for two to four days, coupled with appropriate physical therapy and therapeutic exercise, is often recommended by medical doctors for acute low back pain. However, reviews of bed rest recommendations have concluded that bed rest is, at best, ineffective and may even delay recovery. It is better to try to stay active and maintain a normal daily schedule as much as possible.
General recommendations for people recuperating from low back pain include wearing low-heeled comfortable shoes, sitting in chairs with good lower back support, using work surfaces that are a comfortable height, resting one foot on a low stool if standing for long periods, and supporting the low back during long periods of driving.
Nutritional supplements that may be helpful
Three double-blind trials have investigated the effects of supplementing a combination of the enzymes trypsin and chymotrypsin for seven to ten days on severe low back pain with or without accompanying leg pain. Eight tablets per day were given initially in all trials, but in two trials the number of pills was reduced to four per day after two to three days. One of these trials reported small, though statistically significant improvements, for some measures in people with degenerative arthritis of the lower spine. People with sciatica-type leg pain had significant improvement in several measures in one trial, while another found the enzymes were not much more effective than a placebo. These trials included chronic low back conditions, so their relevance to acute LBP alone may be limited.
Several animal studies and some research involving humans suggest that a synthetic version of the natural amino acid phenylalanine called D-phenylalaline (DPA), reduces pain by decreasing the enzyme that breaks down endorphins. It is less clear whether DPA may help people with LBP, though there are a small number of reports to that effect, including one uncontrolled report of 27 of 37 people with LBP experiencing “good to excellent relief.” In a double-blind trial, University of Texas researchers found that 250 mg of DPA four times per day for four weeks was no more effective than placebo for 30 people with various types of chronic pain; 13 of these people had low back pain. In a Japanese clinical trial, 4 grams of DPA per day was given to people with chronic low back pain half an hour before they received acupuncture. Although not statistically significant, the results were good or excellent for 18 of the 30. The most common supplemental form of phenylalanine is D,L-phenylalanine (DLPA). Doctors typically recommend 1,500–2,500 mg per day of DLPA.
A combination of vitamin B1, vitamin B6, and vitamin B12 has proved useful for preventing a relapse of a common type of back pain linked to vertebral syndromes, as well as reducing the amount of anti-inflammatory medications needed to control back pain, according to double-blind trials. Typical amounts used have been 50–100 mg each of vitamins B1 and B6, and 250–500 mcg of vitamin B12, all taken three times per day. Such high amounts of vitamin B6 require supervision by a doctor.
Proteolytic enzymes, including bromelain, papain, trypsin, and chymotrypsin, may be helpful in healing minor injuries because they have anti-inflammatory activity and are capable of being absorbed from the gastrointestinal tract. Several preliminary trials have reported reduced pain and swelling, and/or faster healing in people with a variety of conditions who use either bromelain or papain.
A preliminary report in 1964 suggested that 500–1,000 mg per day of vitamin C helped many people avoid surgery for their disc-related low back pain. No controlled research has been done to examine this claim further.
Herbs that may be helpful
Colchicine, a substance derived from autumn crocus, may be helpful for chronic back pain caused by a herniated disc. A review shows that colchicine has provided relief from pain, muscle spasm, and weakness associated with disc disease including several double-blind trials. The author of these reports has suggested that 0.6 to 1.2 mg of colchicine per day leads to dramatic improvement in four out of ten cases of disc disease. In most clinical trials, colchicine is given intravenously. However, the oral administration of this herb-based remedy also has had moderate effectiveness. People with low back pain should consult a physician skilled in herbal medicines before taking colchicine due to potentially severe side effects.
Willow bark is traditionally used for pain and conditions of inflammation. According to one controlled clinical trial, use of high amounts of willow bark extract may help people with low back pain. One trial found 240 mg of salicin from a willow extract to be more effective than 120 mg of salicin or a placebo for treating exacerbations of low back pain. Topical cayenne pepper has been used for centuries to reduce pain, and more recently, to diminish localized pain for a number of conditions, including chronic pain, although low back pain has not been specifically investigated. Cayenne creams typically contain 0.025–0.075% capsaicin. While cayenne cream causes a burning sensation the first few times used, this decreases with each application. Pain relief is also enhanced with use as substance P, the compound that induces pain, is depleted. To avoid contamination of the mouth, nose, or eyes, hands should be thoroughly washed after use or gloves should be worn. Do not apply cayenne cream to broken skin.
One double-blind trial found that devil’s claw capsules (containing 800 mg of a concentrated extract taken three times per day) were helpful in reducing acute low back pain in some people. Another double-blind trial (using 200 mg or 400 mg of devil’s claw extract three times daily) achieved similar results in some people with exacerbations of chronic low back pain.
Herbalists often use ginger to decrease inflammation and the pain associated with it, including for those with low back pain. They typically suggest 1.5 to 3 ml of ginger tincture three times per day, or 2 to 4 grams of the dried root powder two to three times per day. Some products contain a combination of curcumin and ginger. However, no research has investigated the effects of these herbs on low back pain.
A combination of eucalyptus and peppermint oil applied directly to a painful area may help. Preliminary research indicates that the counter-irritant quality of these essential oils may decrease pain and increase blood flow to afflicted regions. Peppermint and eucalyptus, diluted in an oil base, are usually applied several times per day, or as needed, to control pain. Plant oils that may have similar properties are rosemary, juniper, and wintergreen.
Turmeric is another herb known traditionally for its anti-inflammatory effects, a possible advantage for people suffering from low back pain. Several preliminary studies confirm that curcumin, one active ingredient in turmeric, may decrease inflammation in both humans and animals. In one double-blind trial, a formula containing turmeric, other herbs, and zinc significantly diminished pain for people with osteoarthritis. Standardized extracts containing 400 to 600 mg of curcumin per tablet or capsule are typically taken three times per day. For tinctures of turmeric, 0.5 to 1.5 ml three times per day are the usual amount.
Holistic approaches that may be helpful
Acupuncture may be helpful in the treatment of low back pain in some people. Case reports and numerous preliminary trials have described significant improvement in both acute and chronic back pain following acupuncture (or acupuncture with electrical stimulation) treatment. In a single controlled study of acute back pain, both electroacupuncture and drug therapy (acetaminophen) led to statistically significant pain reduction and improved mobility.
Several controlled clinical trials have evaluated acupuncture for chronic low back pain. A controlled trial found acupuncture was significantly superior to placebo (fake electrical stimulation through the skin) in four of five measures of pain and physical signs. Controlled trials using electroacupuncture have reported either benefit or no benefit for chronic back pain. A double-blind trial compared acupuncture to injections of anaesthetic just below the skin at non-acupuncture points, and found no difference in effect between the two treatments.79 Controlled trials have compared acupuncture to transcutaneous nerve stimulation (TENS). Some, though not all, demonstrated greater pain relief with acupuncture when compared to TENS, and one found improved spinal mobility only with acupuncture.
In one preliminary trial, acupuncture relieved pain and diminished disability in the low back during pregnancy better than physiotherapy.
A recent analysis and review of studies reported acupuncture was effective for low back pain,85 though another recent review concluded acupuncture could not be recommended due to the poor quality of the research. A third review concluded that acupuncture was beneficial for people with slipped discs and sciatica and could be recommended at the very least as a supplementary therapy. Since the vast majority of controlled acupuncture research addresses chronic low back pain, it remains unknown whether people with acute low back pain benefit significantly from acupuncture.
The federally funded Agency for Health Care Policy and Research has deemed spinal manipulation effective for acute low back pain during the first month following injury. This recommendation is supported by other research, though some has not been well controlled. People whose initial pain or disability is severe to moderate appear to benefit the most, though those with longer lasting or chronic pain may also be helped by spinal manipulation. One 12-month controlled study found no difference in benefit between manipulation and standard physical therapy. Another controlled study found a series of eight treatments with spinal manipulation was as effective as conventional medical therapy, but the manipulation group needed less pain medication and physical therapy.
Practitioners who perform spinal manipulation include chiropractors, some osteopaths, and some physical therapists.
Some researchers suggest that spinal manipulation should not be performed on people with a herniated (slipped) disc, because it may lead to spinal cord injuries. However, other preliminary trials report that spinal manipulation helps those with herniated discs, as did one controlled study comparing manipulation to standard physical therapy. In one investigation of 59 people with slipped discs who received chiropractic treatment, including manipulation, 90% reported improvement. Those with a history of low back surgery had poor outcomes. People with LBP due to herniated discs who wish to try this method should first consult with a chiropractor or other physician skilled in spinal manipulation. A recent controlled study compared manipulation, acupuncture, and medication for chronic spinal pain. Only manipulation significantly improved pain and disability scores.
There is inconclusive evidence that massage alone helps people with low back pain, though preliminary research indicates it has potential. Many practitioners use massage in combination with other physical therapies, such as spinal manipulation or therapeutic exercise. People with low back pain who want to try massage should consult with a qualified massage therapist.
Some controlled trials indicate that biofeedback benefits people with chronic low back pain, but other trials do not. One study found that biofeedback was more effective than behavioural therapy or conservative medical treatment for people with chronic back pain. The study also found biofeedback to be the only method where people experienced significant reduction in pain for up to the two years of follow-up. People wishing to try biofeedback should discuss this method with a qual