In fact, a high consumption of fruit, vegetables and mushrooms is linked to a lower risk of gout. A wholesome diet, such as the traditional Mediterranean diet, is associated with a lower risk of gout. Advice to gout sufferers to avoid foods such as spinach, asparagus and mushrooms is not justified.
Gout is a type of arthritis that is characterised by high levels of uric acid in the blood (hyperuricaemia), and is more likely to occur in men than in women. The high levels of uric acid can trigger the deposition of sodium urate crystals in joints, causing intense pain (Shils 2006).
Uric acid is an end-product compound from the breakdown of purines made within the body and purines consumed in the diet. Uric acid is normally eliminated via the kidneys such that uric acid stays at normal levels. High levels are thought to be due to reduced elimination, increased production, the consumption of high-purine foods, or a mix of all three. Some medications, such as those for high blood pressure, can also raise uric acid levels.
Gout has long been associated with overweight, binge eating and alcohol consumption. Losing weight and avoiding alcohol is common advice for many people with gout as this reduces the incidence of gout attacks. Healthy eating is advised as many gout sufferers are also at high risk for heart disease and diabetes.
Alcohol consumption, especially beer, is strongly associated with gout. Alcohol reduces uric acid losses via the kidneys (Choi 2004; Lee 2006; Yu 2008).
The most common and effective treatment for gout is through medication such as uricosuric drugs that increase the excretion of uric acid via the kidneys. Modifying the diet to avoid very high purine foods may have an additional minor benefit with drug therapy, although dietary changes rarely lower serum uric acid by more than 10-20% (Fam 2005; Shils 2006). This small lowering of uric acid is not thought to be of therapeutic benefit in many gout sufferers (Khanna 2012).
There is now evidence that most purine-containing food, especially non-animal food, has little influence on gout. In the past, the most common dietary advice was to avoid purine-rich foods like animal flesh and offal, seafood, yeast extracts, peas, legumes, lentils, spinach, asparagus and mushrooms. It is not clear why spinach, asparagus and mushrooms were mentioned so frequently, as green peas, broccoli and Brussels sprouts have more purine yet are never mentioned in text books or websites giving dietary advice on gout.
Foods such as dairy foods, possibly due to the dairy proteins, and vegetables, even those with moderate purine content, seem to be protective against gout (Lee 2006; Choi 2004; Choi 2010; Zgaga 2012). One paper showed that coffee reduces gout risk (Chuang 2011). Those who most closely followed a traditional Mediterranean had the lowest uric acid levels and less likely to have high uric acid levels associated with gout (Kontogianni 2012).
Non-animal foods not linked to gout
There is no evidence that a vegetable or mushroom with a modest amount of purine will raise uric acid levels and trigger a gout attack. A study of over 47,000 men over a period of 12 years (aged 40-75 yrs at the start of the study) found that a “moderate intake of purine-rich vegetables is not associated with an increased risk of gout”, whether purine-rich vegetables were considered as a food group or as individual vegetables (Choi 2004).
Another study of 92 men with gout and 92 controls found no link between purine intake and the occurrence of gout, or between fruit and vegetable intake and gout (Lyu 2003). In fact, the authors state that: “Our data support the observation that increased consumption of foods from plant sources, especially fruit and vegetables, reduce the risk of gout development.”
A review of the lifestyle evidence to reduce gout attacks specifically mentions to consume purine-rich vegetables “as they do not increase the risk of gout.” (Choi 2010). The review goes on to say that people who ate the most vegetable protein actually had a 27% lower risk of gout compared with those that ate the least.
A study of over 2000 adults concluded that: “… we found no association between purine-rich vegetables consumption and plasma urate” (Zgaga 2012). The authors said that their results reinforced the concerns about recommendations that restrict the eating of purine-rich vegetables. However, they did find an association between plasma uric acid and sugar-sweetened drinks.
Two surveys of Taiwanese adults showed an inverse relationship between vegetables, mushrooms and gout risk (Chuang 2011). The more mushrooms consumed, the lower the average uric acid levels.
A review of gout management by the American College of Rheumatology recognised that dietary changes alone did not sufficiently lower plasma uric acid levels for many people with gout, and specifically encouraged the consumption of vegetables and low-fat dairy foods (Khanna 2012).
Mushrooms are very low in kilojoules and help control appetite, making them ideal for weight control. As weight loss reduces gout attacks in overweight people, mushrooms can have an additional benefit for the gout sufferer.
The evidence to date strongly indicates that non-animal foods like mushrooms, fruits, legumes, nuts and vegetables may be protective against gout and therefore should not be restricted in those that suffer from gout.