Weight, diet and rheumatoid arthritis

Taken from the NRAS magazine, Spring 2016

by Dr James Galloway, Kings College London and trainee Gloria LlisoAs we enter the second half of the second decade of the 21st century, the global community is growing ever more aware of the health challenges associated with weight. Worldwide there are now over 1 billion adults who fall into the category of ‘obese’. UK estimates now suggest that the NHS is spending more on obesity-related disease than it does on smoking-related illnesses. Indeed, the UK has the highest prevalence of obesity of any Western country, with the proportion of obese adults have risen from just 7% in 1980 to 25% in 2012.The World Health Organisation defines obesity as abnormal or excessive fat accumulation that results a risk to health. A crude measure of obesity is the body mass index (BMI), a person’s weight (in kilograms) divided by the square of his or her height (in metres). A person with a BMI of 30 or more is generally considered obese (see Figure 1). Obesity itself is not a disease, but nonetheless ithas far reaching implications. Obesity is a major risk factor for several illnesses, including diabetes, heart attacks, stroke and cancer.

Definitions of obesity

Despite worldwide acceptance of the problem, as a society we are still in the early days of learning how to help people reduce weight in a sustainable manner. Many diets exist, although the results are mixed, and few studies demonstrate long-term success. Current thinking in the medical arena is that there is a ‘window of opportunity; people who are normal or slightly overweight, but not yet obese, likely represent the group most important to target from a public health strategy.

Studies exploring the frequency of obesity in people with rheumatoid arthritis suggest that the patterns are similar to the general population. However, the situation is different for people with rheumatoid arthritis. We know that rheumatoid arthritis directly impacts upon weight. Patients with arthritis lose muscle bulk (termed ‘sarcopenia’). As muscle is heavier than fat BMI may underestimate obesity in people with rheumatoid arthritis. What is clear is that people with a BMI above 25 with rheumatoid have worse outcomes, reporting more pain and higher levels of disability.

A further challenge facing people with rheumatoid arthritis is how to tackle weight gain. The management of obesity evolves around two aspects: dietary change and increased exercise. People with rheumatoid arthritis are disadvantaged here, as exercise is impacted upon by the inherent nature of the disease. Whilst in general exercise is beneficial for joints - in particular it helps strengthen the surrounding muscles - it can be painful. During times of disease flare it is important to try and rest particularly inflamed joints but it is equally important to keep moving and exercise a limited amount.

In addition, doctors often prescribe corticosteroid tablets (e.g. prednisolone) as a treatment for rheumatoid, and a direct side effect of corticosteroids is weight gain.

The positive news however is that studies have shown that by far the most important step in achieving weight loss is dietary change: research shows that compared to diet alone, exercise plus diet only has a small additional benefit on weight loss.

Advice on diet

BMI chart

Many patients, who enquire about diet and arthritis, are specifically interested to know whether a certain diet is beneficial for their symptoms. Unfortunately this is challenging to answer. Whilst there is no doubt whatsoever that many people with rheumatoid notice diet influences their joint pains, everyone seems to be slightly different. Recommending a one-size fits all diet as a panacea for rheumatoid is therefore unhelpful. Studies (and there have been many) have failed to convincingly show any one diet has specific benefit for rheumatoid arthritis.

Therefore, the most sensible and pragmatic advice is to adhere to the standard recommendations for a balanced diet that apply to the population at large. Individuals may get to know their own particular foods that they need to avoid, but the overarching principles should be as follows:

Appropriate calorie intake:

Maintaining the correct amount of calories in diet is important in achieving a healthy weight. It can sometimes be difficult to know how many calories we should eat. There are a number of online calorie calculators that can help you understand how many calories there are in different types of food. (www.nhs.uk/Livewell/weight-loss-guide to find the calorie counter and much more.). Understanding calorie content in food must then be combined with knowledge of how many calories you need. The amount of calories you need can be estimated from your weight and your daily activities. Again, several free online calculators exist (www.calculator.net/calorie-calculator).

Balancing the source of calories:

A number of guidelines recommend that the total caloric intake should be broken down by percentage of intake according to food type:

  • 45 to 65 % from carbohydrates
  • 10 to 35 % from protein
  • 20 to 35 % from fat

Carbohydrate – there are many sources of carbohydrate and each varies with regards to effect upon your bodies sugar metabolism (referred to as the glycaemic index of the food). Diets containing foods with a low glycaemic index have been associated with lower risks of developing diabetes, coronary heart disease, and some cancers. Therefore an important way of achieving a healthy diet is to replace carbohydrates having a high glycaemic index (e.g., pizza, rice, pancakes) with a low glycaemic index (e.g., fruits, vegetables). It is also important to try to reduce foods with added sugars (as opposed to natural sugars). Many prepared foods and ready meals contain astonishing amounts of added sugar, as do soft drinks and alcoholic beverages.

Protein – it is healthier to eat a variety of protein-rich foods, including fish, lean meat such as poultry, eggs, beans, peas, soy products, and unsalted nuts and seeds. Studies suggest that it is better to avoid protein sources with trans and saturated fats, including red and processed meats.

Fat – consumption of fat in diet has always been controversial. It appears that the type of fat is as important as the quantity of fat in our diets. So called ‘trans’ fats contribute to coronary heart disease, while polyunsaturated fats (found in oily fish) are protective. Trans fatty acid consumption should therefore be kept as low as possible. The major sources of trans fats include margarines and partially hydrogenated vegetable fats. These fats are also present in many processed and fast foods.

Fibre – the current recommendations are that adults consume at least 5 items of fibre (fruit/veg) every day. The evidence for the benefit of high fibre diets is strong, with studies showing lower risks for heart disease, diabetes, cancer and death. Foods high in fibre include fruits, vegetables and whole grains (brown rice, whole grain bread, oatmeal).

Getting support:

It is all very well describing what an ideal diet might include, but we all know that there is a reason why people chose to eat less healthy options. Foods higher in refined sugars and salt taste better (in fact there is good evidence that such diets are addictive). Eating is also enjoyable and has a pivotal role in society, bringing families and friends together. Setting out to change your diet as a solo venture is an enormous task. Thankfully, there are now many weight loss groups available (e.g. weightwatchers, slimming world) that can help. A crucial advantage of dieting as part of a group is the motivational support obtained. Many GPs are now able to refer to weight loss classes, although sometimes having to pay a membership to a group can be a motivation to attend in its own right!

In summary:

There is no doubt that the rising spectre of obesity in western society is going to have dramatic adverse consequences for society. The impact of obesity for people living with rheumatoid arthritis is exaggerated further, linking with more pain and greater levels of disability. However, having rheumatoid arthritis should not be perceived as a barrier to weight loss.