Introduction
Aims
Methods
Areas of variation in dietary advice given to patients by BIMDG dietitians:
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Use of different terminology to describe low protein foods that could be incorporated into the diet without measurement. | |
Inconsistent advice to parents about the calculation of 1 g protein exchanges (equivalent to 50 mg phenylalanine) from protein labelling analysis of individual food portions i.e. dietitians were either rounding protein values > or < 1 g to the nearest 0.5 exchange. | |
Use of different upper protein ‘cut off’ points for foods that could be given in the diet without measurement (exchange-free). There was inconsistent allocation of the following foods: herbs and spices; fats/oils; soya sauce; gravy; cooking sauces; vegetable crisps; sweets; and processed vegetables/vegetable sauces with protein containing ingredients (e.g. milk/wheat). | |
Inconsistent allocation of manufactured foods that contained low protein (exchange-free) ingredients. | |
Inconsistent allocation of special low protein foods that contained low protein (exchange-free) ingredients. | |
Inconsistent allocation of fruits and vegetables (containing phenylalanine from 50 to 100 mg/100 g weight) in the diet. Some dietitians were allowing certain fruits and vegetables in the diet without measurement; others were permitting in restricted amounts only. | |
Inconsistent interpretation of manufactured food labelling: e.g. some foods are labelled as containing 0 g protein even though some of the ingredients are protein sources. This includes foods containing protein ≤0.5 g/100 g (permissible by European law: Regulation (EU) No 1169/2011) [4] or protein < 1 g/100 g (permissible by USA law). |
Results
Phase 1: Round 1 of Delphi method
PHASE 1
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Consensus statements | Delphi Process – Round 1 % agreement (n) | Delphi process – Round 2 % agreement (n) | Delphi process – Round 3 % agreement (n) | |||
Paediatric Dietitians n = 29 18 centres | Dietitians in adult practice n = 17 11 centres | Paediatric Dietitians n = 36 18 centres | Dietitians in adult practice n = 19 12 centres | Paediatric Dietitians n = 25 10 centres | Dietitians in adult practice n = 20 13 centres | |
In PKU, low protein, free, unmeasured or non-exchange foods are referred to as ‘exchange-free’ foods. | 93 (27) | 100 (17) | Agreed | Agreed | Agreed | |
Foods are ‘exchange-free’ if protein content is ≤ 0.5 g/100 g of food:
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• e.g. sweets | 90 (26) | 88 (15) | Agreed | Agreed | Agreed | |
• e.g. gravy | 97 (28) | 76 (13) | Agreed | Agreed | Agreed | |
Exceptions that remain ‘exchange-free’ if > 0.5 g per 100 g or per 100 ml of food:
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• all herbs, spices and seasonings (irrespective of the protein content on the food ingredient label, due to the small quantities consumed); | 100 (29) | 100 (29) | Agreed | Agreed | Agreed | |
• fats (oils, butter, margarine) (as only small amounts are used) | 100 (29) | 88 (15) | Agreed | Agreed | Agreed | |
• ‘wet cooking sauce’ if the protein content is ≤1.0 g/100 g | 100 (29) | 65 (11) | Agreed | Agreed | Agreed | |
Soya sauce:
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ROUND 1: soya sauce that contains Phe ≤ 1.0 g/100 ml (based on the quantities commonly consumed) | 97 (28) | 88 (15) | N/A | N/A | N/A | |
ROUND 2:
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• Option 1: Any soya sauce that contains protein ≤1.0 g/100 ml is considered ‘exchange-free’ | N/A | N/A | 25 (9)* | N/A | N/A | |
• Option 2: Any soya sauce that contains protein ≤1.5 g/100 ml is considered ‘exchange-free’ | N/A | N/A | 67 (24)* | Agreed | Agreed | |
• Option 3: 2 tablespoons per day of any soya sauce is ‘exchange-free’ (existing guideline) | N/A | N/A | 14 (5)* | N/A | N/A | |
For ‘wet cooking sauces’ with a protein content > 1.0 g /100 g:
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• If they contain exchange ingredients (e.g. cream, egg, coconut) they are counted as an ‘exchange’ food; | 100 (29) | 65 (11) | Agreed | Agreed | Agreed | |
• If they contain ‘exchange free’ ingredients only (e.g. fruit/vegetables) they are considered an ‘exchange-free’ food. | 100 (29) | 65 (11) | Agreed | Agreed | Agreed | |
Allocation of fruits and vegetables (except fresh/frozen potatoes)
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ROUND 1: | ||||||
• Fruits & vegetables (except potatoes) containing a Phe content ≤75 mg/100 g weight will be consisdered ‘exchange-free’ foods. | 100 (29) | 100 (17) | Agreed | Agreed | Agreed | |
• Fruits & vegetables with a Phe content of ≥100 mg/100 g, use the actual Phe content to calculate exchange amounts. | 100 (29) | 100 (17) | Agreed | Agreed | Agreed | |
• Phe content 76-99 mg/100 g weight of fruit & vegetable: allow 1 portion/day ‘exchange-free’ | 86 (25) | 82 (14) | N/A | N/A | N/A | |
ROUND 2/3: | ||||||
• Option 1: Fruit & vegetables containing a Phe content 76–99 mg/100 g weight of fruit & vegetable, count as ‘exchange’ foods | N/A | N/A | 35 (13)* | 64 (16) | Agreed | |
• Option 2: Allow 1 exchange portion ‘exchange-free’ per day with additional portions to be counted as an exchange | N/A | N/A | 42 (15)* | 24 (6) | ||
• Option 3: Only 1 portion of these fruits/ vegetables are allowed ‘exchange-free’ per day (existing guideline) | N/A | N/A | 33 (12)* | |||
Additional statement: Fruits & vegetables containing a Phe content of 76–99 mg/100 g, use a standard ‘exchange’ amount of 60 g weight to provide approximately 50 mg/Phe | N/A | N/A | 97 (35) | Agreed | Agreed | |
• Fresh/frozen potatoes are counted as ‘exchange’ foods. If the Phe analysis is available, this will be used to determine exchange amount; if Phe analysis is unavailable (e.g. potato waffles, hash browns), the protein content will be used to calculate exchange amounts. | 97 (28) | 94 (16) | Agreed | Agreed | Agreed | |
• Manufactured fruit/vegetable products containing only fruits or vegetables that are designated as ‘exchange-free’ in their fresh form, should still be considered ‘exchange-free’ foods. However, if they contain added ingredients that are protein containing (e.g. milk or wheat), they are counted as ‘exchange’ foods with their protein content used to determine the amount of food allocated for one Phe exchange. | 100 (29) | 88 (15) | Agreed | Agreed | Agreed | |
• Vegetable crisps containing exchange free vegetables are counted as ‘exchange’ foods due to the concentration of protein associated with cooking methods; their protein content should be used to determine the exchange amount. | 88 (21) | 88 (15) | Agreed | Agreed | Agreed | |
Low protein special foods:
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• Low protein special products (e.g. bread, flour) should be allowed without measurement if all ingredients are ‘exchange-free’, irrespective of the phenylalanine analysis per 100 g on the label. | 93 (27) | 76 (13) | Agreed | Agreed | Agreed | |
alculating food protein exchanges from protein analysis on the food label:
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• Food ‘exchange’ amounts for food portions should be rounded up or down based on the ‘rule of maths’ (Table 3 for guidance). | 97 (28) | 94 (16) | Agreed | Agreed | Agreed | |
• Patients/caregivers are advised to read ingredient lists as well as the protein content on food labels. The following was concluded as guidance: | 100 (29) | 88 (15) | Agreed | Agreed | Agreed | |
- If ingredients contain protein but the protein label content appears low, establish a more accurate protein analysis before consuming. | 100 (29) | 88 (15) | Agreed | Agreed | Agreed | |
- If ingredients are ‘clearly’ exchange-free but the protein label content is not available then it is suitable to give as an exchange-free food. | 100 (29) | 100 (17) | Agreed | Agreed | Agreed | |
- If there is no protein content on the product label, but it contains exchange ingredients, an accurate protein analysis should be obtained before consuming. | 100 (29) | 100 (29) | Agreed | Agreed | Agreed | |
- If a label states its protein content is 0 g but ≥1 ingredient contains a protein source (e.g. gelatine), avoid until an accurate protein analysis is known. | 97 (28) | 65 (11) | Agreed | Agreed | Agreed | |
Agree with all consensus statements (as above) | N/A | N/A | N/A | N/A | N/A | 75 (15) |
Separate maternal PKU statements preferred | N/A | N/A | N/A | N/A | N/A | 40 (8) |
PHASE 2 | ||||||
Consensus statements | Delphi Process – Round 1 % agreement (n) | Delphi process – Round 2 % agreement (n) | Final Decision | |||
Paediatric Dietitians n = 19 13 centres | Dietitians in adult practice n = 9 8 centres | Paediatric Dietitians
n = 19
11 centres | Dietitians in adult practice n = 14 8 centres | |||
Low protein milk
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ROUND 1:
| ||||||
• Option 1: A daily volume of 250 ml is exchange free if it provides ≤0.5 g protein (25 mg Phe)/daily | 16 (3) | 56 (5) | N/A | N/A | ||
• Option 2: A daily volume of 500 ml/daily volume is exchange free if it provides ≤0.5 g protein (25 mg Phe) /daily | 42 (8) | 11 (1) | N/A | N/A | ||
• Option 3: A daily volume of 1000 ml/daily volume is exchange free if it provides ≤0.5 g protein (25 mg Phe) /daily | 21 (4) | 22 (2) | N/A | N/A | ||
• Option 4: A daily volume of 1000 ml/daily volume is exchange free if it provides ≤0.5 g protein (25 mg Phe) /daily | 11 (2) | 11 (1) | N/A | N/A | ||
• Unsure | 11 (2) | – | N/A | N/A | ||
ROUND 2:
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• Any plant milk (e.g. coconut, rice or almond) that provides a total protein intake of > 0.5 g over 24 h when consumed should be counted as an exchange food. If the total protein intake provides ≤0.5 g over 24 h, it should be considered exchange-free. | N/A | N/A | 84 (16) | 79 (11) | Agreed | |
• Any low protein special milk (e.g. Sno Pro, Taranis, Prozero) that provides a total phenylalanine intake of > 25 mg (half an exchange) over 24 h when consumed should be counted as an exchange food. If the total phenylalanine intake provides ≤25 mg over 24 h, it should be considered exchange-free. | N/A | N/A | 79 (15) | 71 (10) | Agreed | |
Soups that contain exchange-free ingredients are exchange-free. | 79 (15) | 78 (7) | N/A | N/A | Agreed | |
Any coconut yoghurt/dessert with a protein content ≤0.5 g/100 g is exchange-free. | 79 (15) | 56 (5) | N/A | N/A | Agreed | |
Any dried coconut product with a protein content > 0.5 g/100 g should be counted as an exchange food. | 95 (18) | 89 (8) | N/A | N/A | Agreed | |
Any food containing ≤0.5 g/100 g protein (but contains gelatine) can be allocated as exchange-free as it is likely to contain ≤10 mg phenylalanine from this source. | 95 (18) | 89 (8) | N/A | N/A | Agreed | |
The weight rather than the volume of ice-cream should be used to calculate the protein exchange amount. | 100 (19) | 100 (9) | N/A | N/A | Agreed | |
PHASE 3 | ||||||
Consensus statements | Delphi Process – Round 1 % agreement (n) | Final Decision | ||||
n = 17
13 centres | ||||||
Low protein special foods
| ||||||
If the special low protein food contains exchange ingredients but contains up to 25 mg Phe/100 g, it is exchange-free. If the special low protein food contains exchange ingredients but contains ≥26 mg Phe/100 g, it is an exchange food. | 94 (16) | Agreed |
Protein content per item when calculated from label | Calculated exchange |
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0 g protein per food portion | Exchange free |
0.1 g protein per food portion | Exchange free (if total volume consumed is ≤0.5 g protein) |
0.2 g protein per food portion | Exchange free (if total volume consumed is ≤0.5 g protein) |
0.3 g protein per food portion | Exchange free (if total volume consumed ≤0.5 g protein). Suggest 1 portion is exchange-free, 2 portions is ½ exchangea |
0.4 to 0.7 g protein per food portion | ½ exchange protein |
0.8 to 1.2 g protein per food portion | 1 exchange protein |
1.3 to 1.7 g per food portion | 1.5 exchange protein |
1.8 to 2.2 g per food portion | 2 exchange protein |
2.3 to 2.7 g per food portion | 2.5 exchange protein |
2.8 to 3.2 per food portion | 3 exchange protein |
Phase 1: Round 2 of Delphi method
Fruit and vegetables containing Phe ≥ 76 mg/100 g | Amount for 1 exchange |
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Figs | 60 g |
Asparagus | 60 g |
Beansprouts | 60 g |
Broccoli | 60 g |
Brussel sprouts | 60 g |
Cauliflower | 60 g |
Yam | 60 g |
Sugar snap peas | 60 g |
Mange tout | 60 g |
Whole hearts of palm | 60 g |
Phase 1: Round 3 of Delphi method
NSPKU endorsement
Phase 2: Round 1of Delphi method
Phase 2: Round 2 of Delphi method
Phase 3: Round 1 of Delphi method
1. Any food given without measurement is referred to as an exchange-free food. | |
2. Foods are ‘exchange-free’ if they contain protein ≤0.5 g/100 g. e.g. sweets, coconut products, foods containing gelatine. Exceptions: • herbs, spices, seasonings, fats (oil, butter, margarine) – as the quantity used is very small. • Any soya sauce containing protein ≤1.5 g/100 ml is exchange-free. • Any ‘wet cooking sauce’ containing protein ≤1.0 g/100 g is exchange-free. If it contains > 1 g protein/100 g and contains exchange ingredients (e.g. cream, egg, coconut) it should be counted as an exchange food. If it contains > 1 g protein/100 g and contains ‘exchange free’ ingredients only (e.g. vegetables such as tomatoes) it is an exchange-free food. | |
3. ‘European PKU guideline 2017’ [3] is used for fruit and vegetable allocation: • Phe content ≤75 mg/100 g weight of fruit and vegetables: exchange-free. • Phe content ≥76 mg/100 g weight of fruit and vegetables: count as exchange foods. Exception: Potatoes – use Phe analysis to determine exchange amounts. If potato products contain additional exchange ingredients (e.g. wheat flour, or milk), use protein analysis on the packet to determine its exchange amount. | |
4. A standard exchange amount of 60 g for any fruit/vegetables containing Phe between 76 and 99 mg/100 g will be used. For any fruit/vegetables containing Phe ≥100 mg/100 g (e.g. peas, sweetcorn), the actual Phe content will be used to calculate exchange amounts. | |
5. If any frozen/canned product is designated ‘exchange-free’ in their fresh form, they are considered exchange-free foods e.g. carrots, mushrooms, tomatoes. Exception: Vegetable crisps - although derived from exchange-free food, are concentrated in protein due to cooking methods so should be counted as exchange foods. Use protein content per 100 g to determine the amount that can be given for one exchange. | |
6. Low protein special products (e.g. bread, flour) are exchange-free if all ingredients are exchange-free. If they contain exchange ingredients but contains ≤25 mg Phe/100 g, they are exchange-free. If they contain exchange ingredients but contains ≥26 mg Phe/100 g, they are an exchange food. | |
7. Any low protein special milk that provides a total Phe intake of > 25 mg (1/2 exchange) over 24 h in the volumes consumed, should be counted as an exchange food. If the total Phe intake provides ≤25 mg over 24 h, it should be considered exchange-free. | |
8. Any plant milk (e.g. coconut, rice, almond) that provides a total protein intake of > 0.5 g over 24 h in the volumes consumed, should be counted as an exchange food. If the total protein intake provides ≤0.5 g/100 g over 24 h, it should be considered exchange-free. | |
9. Soups that contain exchange-free ingredients are exchange-free. If soups contain exchange ingredients and their protein content is > 0.5 g/100 g, then they should be counted as an exchange food. | |
10. Weight rather than the volume of ice-cream should be used to calculate the protein exchange amount. | |
11. Food ‘exchange’ amounts for food portions should be rounded up or down based on the ‘rule of maths’. See Table 3 | |
12. All patients/caregivers are advised to read ingredient lists as well the protein content/100 g on food labels. If ingredients are protein containing (but the protein analysis appears very low), it is important to establish more accurate protein analysis before consuming. If ingredients are ‘clearly’ exchange-free, then it is appropriate to give as an exchange-free food even if the protein analysis is unavailable on the label. If there is no nutritional analysis on the product but it contains ingredients that are exchange foods, then further food protein analysis must be obtained before consuming. If a label states protein content is 0 g but one or more ingredients is a protein source (e.g. gelatine), then an accurate food protein analysis must be obtained before consuming. |