Nutritional requirements can be met with blended diet, whether it is used on its own or in combination with commercial enteral formula or oral diet. Adequacy depends wholly on the food choices made by the person preparing the blend.
This part covers estimating and delivering requirements for macro and micronutrients, fluid and fibre.
Dietetic support should be available to everyone preparing blends for tube feeding. The dietitian’s role throughout is to support and advise on the diet as a whole, not to make the everyday or every meal food decisions.
Keep advice in plain language, free of clinical jargon.
1. Estimate nutrition and hydration requirements
Take age, medical condition and energy expenditure into account using standard prediction equations, bearing in mind that requirements may be much lower in non-mobile children and adults.
Protein requirements should be based on recommended intakes, as for oral intake. Predicted requirements are a guide to be used alongside monitoring and should be adjusted as monitoring indicates.
Where a person has been weight-stable, or for children tracking growth centiles on commercial enteral formula, matching current intake may be more practical as a starting point.
2. Split delivery across the day to suit volume tolerance
Daily intake can be met over three to six blends across the day, for example breakfast, lunch, dinner, supper and snacks.
The split depends on volume tolerance per feed and at different times of day. A little-and-often approach is useful where there are volume tolerance issues.
Blended diet can also be used alongside commercial enteral formula to achieve adequate intake, in a wide variety of ways.
3. Advise on nutrients and consistency, not volume
Blended diet does not have a uniform nutrient density, unlike commercial enteral formula, and the liquid needed to reach a suitable consistency varies depending on the food ingredients used. It is therefore not necessary to calculate energy per millilitre.
A blended diet plan cannot be prescribed by a professional in the way a commercial enteral formula can.
Instead, advise on a daily nutritional requirement as a guide and on the consistency required to administer, which can be communicated using the IDDSI framework (Appendix 10).
4. Teach how fluid needs will be met and how to monitor hydration
Hydration is part of nutritional adequacy and is easily overlooked.
The scoping review suggests assuming that around 70 to 75% of the volume of any blend is fluid, as a starting point.
This applies whether blended diet is the sole source of nutrition or used alongside commercial enteral formula.
Alongside water flushes and medication, this counts toward daily fluid intake.
Where calculated intake falls short, assess output and clinical signs before increasing fluid, such as decreased or dark urine, particularly during illness or in warm weather, when meeting fluid needs is harder and should be discussed. Prediction equations can overestimate needs in this group.
5. Educate on healthy eating and age-appropriate portion sizes
The NHS Eatwell Guide is the starting point for how a blended diet should be constructed from the age of two, with a variety of foods from each of the four main groups: starchy carbohydrates, protein sources, fruit and vegetables, and dairy foods or alternatives.
It does not apply under the age of two, where complementary feeding guidance applies instead.
Healthy eating guidance may need modifying, for example in the case of high or low energy requirements, food allergies, a ketogenic diet or metabolic conditions.
Not everyone arrives with a working knowledge of nutrition or portion sizes, and translating the guide into practical and accessible terms is itself a core dietetic skill.
6. Encourage a variety of foods from each of the food groups
Eating a variety of foods from the different food groups ensures adequate micronutrient intake, and variety should extend across days and weeks rather than repeating the same recipe.
Some foods are harder to blend, and people may choose to leave them out as a result.
Starchy carbohydrates thicken on blending and need additional fluid. Added fats and oils may separate in storage. Meat can be difficult to blend, depending on the cut and cooking method.
Watch for these foods being avoided, and for over-reliance on fruit and vegetables, which blend easily but are low in energy and can lead to carotenaemia, which causes an orange tint to the skin, especially palms and soles of the feet, but is easily reversible.
7. Increase fibre slowly to tolerance, with sufficient fluid alongside
Fibre has a beneficial effect on long term gut health and should be encouraged.
However, sudden introduction or increase in fibre intake can cause either loose stools or constipation, and individual responses are variable and unpredictable.
Aim initially to match previous fibre intake, then slowly increase variety and amount towards the dietary reference value for age. Higher fibre intakes need more fluid, so make sure fluid requirements are met.
8. Do not supplement micronutrients routinely
Follow national public health guidance unless the person’s diagnosis, treatment, biochemistry or dietary analysis indicates otherwise.
Where a wide variety of foods is used, most people need no supplementation, with vitamin D the usual exception.
Where a shortfall has been documented it is rarely confined to one nutrient.
A wide range of products carrying health claims that are not supported by evidence are marketed to the general population.
Where supplementation is wanted, suggest a product with a balanced nutrient profile rather than a high dose of any single micronutrient.
Where a clinical deficiency is identified, treat it in line with local protocols.
9. Treat any recipe analysis as an estimate, not a measurement
Laboratory analysis of blends has shown that the energy and nutrient content actually delivered can differ from values calculated from food composition tables or product labels.
The energy and nutrients actually delivered are usually lower than the calculated figures, so analysis may overestimate intake, and monitoring takes precedence.
This does not mean the blend is inadequate, only that the calculation is less reliable than it looks, so growth, weight and clinical review are the better guide.
Simple dietetic tools such as 24-hour recall or food frequency can confirm that a variety of foods is being used.
Reserve detailed analysis for therapeutic diets, multiple exclusions, where whole food groups are omitted, or where the household relies heavily on the same ingredients on repeat.
Encourage families to rotate a wide variety of foods to avoid this.
10. Reflect the household’s usual diet
Blended diet is an opportunity for the tube-fed person to share the same foods as their family, so the diet should reflect what the household normally eats, while keeping the variety and balance in points 5 and 6. This is also a useful starting point (Part 8).
For some families, it is a chance to improve the diet of the whole household, and the dietitian can support them to make healthy, varied choices for everyone.
11. Therapeutic or modified diet can be blended
Dietitians are skilled at supporting people to modify their diet in the treatment of disease.
Any therapeutic or modified diet that is used orally can also be blended and given through a tube.
This affects food choices and takes more planning and preparation, so specialist dietetic support is likely to be needed.