Dietary Advice

There is no specific diet that is suitable for all kidney cancer patients. Each person has specific needs depending on where they are in the kidney cancer treatment pathway and the stage of their disease. Their diet will also depend on the presence of co-morbidities, such as diabetes, chronic kidney disease and chronic heart disease. If the patient is in doubt about their diet, they need to discuss it with their GP who can refer them to a registered dietitian. Kidney cancer patients also need to be mindful that if they investigate a diet for kidney disease on the Internet they will get a lot of information that is not suitable or applicable for kidney cancer patients.

Liz Bradly, Specialist Dietitian very kindly filmed a presentation on ‘Nutrition with Kidney Cancer’. We hope you find this helpful.

Kidney cancer patients should try to eat a healthy, well balanced diet. The ‘eatwell plate’ helps patients to get the balance right. It shows the proportion of each food group that should be consumed for a healthy diet. About one third of a healthy diet should be fruit and vegetables, one third carbohydrates, such as bread, rice, potatoes, pasta and other starchy foods, and the remaining third should be composed of milk and dairy foods, meat, fish, eggs, beans, and a small proportion of foods high in fat and/or sugar. A healthy diet is very important because it provides sufficient energy and nutrients to prevent a deficiency in any particular nutrient, helps to optimise health, and reduces the risk of disease.

The body mass index (BMI) is used to determine whether a person has a healthy weight for their height. It is calculated by dividing weight in kilograms by height in meters squared. BMI is not specific for different ethnic groups, for example black people have a larger proportion of muscle mass in their bodies, and because muscle weighs more than fat they may appear to be overweight on the chart.

To eat healthily it is important to have enjoyable meals, a regular meal plan and a good balance of starchy foods, fibre, fats, sugar, salt, fruit, vegetables and alcohol.

Regular meal plan

A regular intake of meals ensures that energy is spread throughout the day; it prevents peaks and troughs in blood sugar levels and prevents the temptation to overeat and binge. If people don’t eat regularly, they can tend to binge and put on weight. Patients should try to eat regular meals and not skip meals, especially breakfast, which is the most important meal of the day because it breaks the overnight fast. Many studies have shown that eating regular meals can help with weight loss.

Starchy foods

Starchy foods, such as potatoes, rice, cereals and pasta, are important in the diet because they are the main source of energy for the body. Patients should aim to include some starchy food in each meal. Whole grain varieties of starchy food, such as brown rice and wholemeal bread, also contain fibre. Starchy foods are a good source of B vitamins needed to support and increase the rate of metabolism, and also contain some calcium and iron.

Fibre

Most people’s diet does not contain enough fibre and people need to aim for 18 g of fibre a day. Fibre helps the digestive system to process food and absorb nutrients. A healthy diet needs fibre to reduce the risk of bowel cancer and constipation, and reduce the level of cholesterol in the blood. Fibre also contributes to the control of blood sugar levels that may also help to control appetite. There are two types of fibre; insoluble fibre is found in brown rice, pasta, bread, lentils, beans, oats and pulses, while soluble fibre is found in all fruit and vegetables, and is high in oats, strawberries, pears and barley. Drinking plenty of water enhances the effectiveness of fibre.

Fats

Fats are a concentrated source of energy and provide the fat-soluble vitamins A, D, E and K; we all need fat in our diets. Fats are required to protect organs, and are involved in metabolism and tissue repair. There are two main types of fat; saturated and unsaturated.

Saturated fats come from animal products, such as meat, full fat milk, cream, full fat yogurts, butter, cheese, ghee, and hydrogenated margarine. Trans fatty acids (a type of saturated fat) are present in processed foods, such as cake, biscuits, crisps etc. and are added to food to prolong shelf life. Both saturated and trans fats should be limited in a healthy diet because they raise cholesterol levels and may contribute to the risk of certain cancers, stroke and heart disease.

Unsaturated fats are found in vegetable oils (e.g. olive oil), seeds, oily fish (e.g. mackerel, pilchards, sardines, trout and herring), nuts, avocados and soft margarine, and are a healthier alternative to saturated fats. Unsaturated fats contain essential fatty acids that can’t be made by the body and omega 3, which can protect against heart disease.

Fat can be reduced in the diet by;

• Using lean cuts of meat and removing any visible fat from the meat before cooking, such as fat on red meat and the skin from chicken.
• Using less butter and opting for a vegetable-based spread or oil.
• Grilling, steaming or baking food, rather than frying.
• Choosing low fat dairy products, such as semi-skimmed milk, and low fat yogurts and cheeses.
• Taking fruit, seeds or nuts as a snack rather than biscuits, cakes or crisps.

Fruit and vegetables

Fruit and vegetables are a very important component of a healthy diet. They are high in fibre, especially soluble fibre, and therefore may help to reduce the incidence of some bowel cancers. Fruit and vegetables also help to reduce blood cholesterol levels and control blood sugar levels. However, fruit can increase blood sugar because it contains fructose, a sugar found naturally in fruit. Fruit and vegetables are also a good source of antioxidants, vitamins and minerals, which are essential for the body, and are low in calories.

A healthy diet should contain at least five portions of fruit and vegetables from a variety of sources a day. One portion is one glass of unsweetened fruit juice (150 ml), one medium fruit e.g. an apple or an orange, two tablespoons of vegetables, one small bowl of side salad, two small fruits e.g. plum or satsuma, or one handful of berries or dried fruit. Kidney cancer patients should not avoid eating bananas, but do not eat excessive amounts as they are rich in potassiuma and kidney function can be compromised following a nephrectomy.

Salt

Most of the salt in our diets comes from the salt added to processed food during the manufacturing process. Bread contains one of the highest amounts of salt of all the foodstuffs we eat. Most of us eat about 12 g of salt per day; the National Institute of Health and Care Excellence (NICE) have set a target for the population to reduce salt intake to 5 g per day by 2015, and 3 g per day by 2020. High salt intake is linked to high blood pressure. Food manufacturers are looking at ways to reduce the amount of salt they add to processed food by looking at alternative flavours, such as potassium chloride. However, this could have implications for patients with compromised kidney function. A shop-bought ready meal contains about 3 g of salt; this can be reduced to 1 g by preparing a meal at home and avoiding the use of stock cubes. One stock cube contains about 4 g of salt while one teaspoon is 5 g.

Salt intake can be reduced by:

• Keeping salt off the dinner table – try food before putting salt on!
• Using herbs and spices for flavouring, such as garlic, thyme, rosemary and lemon.
• Being aware that stock cubes, seasoning and ready-made sauces often contain lots of salt.
• Avoiding smoked and cured foods that contain high levels of salt.
• Avoiding salt substitutes, such as Lo-salt, since these contain lots of potassium.
• Rock salt and sea salt are no healthier than normal table salt!

Sugary treats

Life is for living, so patients are allowed some sugary treats; however, sugary treats should be eaten in moderation. Sugary treats should be eaten after a meal to prevent large fluctuations in blood sugar levels, which is especially important for diabetics. Sugar provides empty calories and if eaten in excess will contribute to weight gain and also tooth decay.

Sugar intake can be reduced by;

• Drinking diet fizzy drinks or drinks without any added sugar.
• Using sweeteners instead of sugar in tea and coffee or cut back on the sugar until no longer needed or wanted.
• Ensuring that fruit juice is not sweetened.

Sweeteners, such as aspartame, saccharin and sorbitol, are used to reduce the calorie content of food. The Food Standards Agency (FSA) governs the use of sweeteners in the manufacturing of food. In animal studies, there is some concern that high levels of sweeteners in food are associated with the development of bladder cancer; however, this has not been proven in humans. Low fat foods tend to have more sugar or sweeteners added to compensate for the low fat levels.

Alcohol

The government’s recommended safe intake of alcohol is 14 units per week for both women and men, with one unit being a single pub measure of spirit, 125 ml glass of wine, or half a pint of beer or lager. Like sugar, alcohol provides calories devoid of nutritional benefit (empty calories). There is about 100 calories in a glass of wine.

Food labelling

Food labelling has improved considerably in recent years, but is still sometimes very difficult to interpret. However, the green-amber-red system is used more frequently on supermarket foods and helps to direct people to more healthy options.

Supplements

Vitamin or mineral supplements are not needed if you eat a varied and healthy balanced diet, and the use of excessive supplements can be harmful to health. As we get older, bone health becomes more important and exposure to the sun to increase vitamin D production can help with this. Exposure of the skin to ultraviolet light from the sun results in the production of vitamin D by the skin cells. The use of high factor sun creams can lead to vitamin D deficiency since the creams block the action of the sun on skin to reduce vitamin D production by the body.

Functional foods

Pre- and probiotics promote the growth of the good bacteria in the gut and are important for good digestive system health. They can help with the digestion of food and prevent tummy bugs. They may be added to some vitamin and mineral supplements, yogurts and yogurt drinks, and can be bought at most supermarkets and health food shops.

Plant stanols and sterols are clinically proven to reduce the absorption of cholesterol from the gut, therefore lowering the amount of bad cholesterol (low density lipoprotein, LDL) in the blood. They need to be consumed according to the manufacturer’s instructions to confer any benefits.