Optimal - The Blog

June 5, 2023

Nutrition Screening: You May Be Surprised What You'll Find

Nutrition screening should be performed by a specialist (e.g., a dietitian) using subjective and objective parameters such as clinical history, physical examination, body composition measurements, functional assessment, and laboratory values.

A set of laboratory parameters in the clinical routine (e.g., complete blood count, lipid profile, electrolytes, liver parameters) may provide valuable information about a patient’s nutritional status (e.g., proof of nutrient deficiency, information about the etiology of malnutrition, follow-up nutritional therapy), about the severity and activity of the disease, and about changes in body composition.

Laboratory values—particularly in chronically malnourished patients—may help to detect deficiencies in vitamins (C, D, E, K, thiamin, B6, B12, and folate) and trace elements (zinc, selenium, and iron) and help to monitor current substitution therapies. In the early phase of refeeding, potassium, phosphate, and magnesium deficiencies may occur, potentially leading to severe complications (e.g., refeeding syndrome); hence, there is a need for close monitoring of these electrolytes.

Laboratory values to detect malnutrition and monitor nutritional status


Nutrition Independent Factors

1/2 -Life

Appropriate to Detect

Appropriate to Monitor Nutritional Therapy


↑ dehydration

20 d


Not appropriate due to high suggestibility and long half-life

↓ inflammation, infections, trauma, heart failure, edema, liver dysfunction, nephrotic syndrome

Not appropriate in case of anorexia and acute illness


↑ renal failure, iron status, acute hepatitis, hypoxia

10 d



↓ inflammation, chronic infections hemochromatosis, nephrotic syndrome, liver dysfunction

Low sensitivity and specificity

Concentration is independent of the energy and protein intake

Prealbumin/Transthyretin (TTR)

↑ renal dysfunction, dehydration, corticosteroid therapy

2 d



Not appropriate to detect anorexia Subnormal values within one week in case of fasting

One of the most appropriate proteins

↓ inflammation, hyperthyreosis, liver disease, overhydration

Retinol binding protein (RBP)

↑ kidney failure, alcohol abuse

12 h

Idem prealbumin

Idem prealbumin

↓ hyperthyreosis, chronic liver diseases, vitamin A deficiency, selenium deficiency

Insulin-like growth factor 1 (IGF-1)

↑ kidney failure

24 h



More specific than retinol-binding protein and prealbumin/ transthyretin

↓ liver diseases, severe catabolic status, age

Rapid decrease in fasting periods

Urinary creatinine

↑ collection time >24h, infection, trauma


1 mmol of creatinine is derived from 1.9 kg of skeletal muscle mass

Not appropriate, very slow

↓ insufficient collection time, acute kidney failure


↑ healing phase after infection, hematologic diseases



Not appropriate, very slow

↓ sepsis, hematologic disease, immune suppressants, steroids

Very unspecific

Physical examination is an objective method of detecting clinical signs and symptoms of nutritional deficiencies of vitamins and minerals (e.g., poor muscle control, night vision impairment, vertical lip cracks, depression), and allows the assessment of tolerance to nutritional support (e.g., abdominal distention, vomiting, diarrhea).

Some clinical signs are specific to a specific disease or nutrient deficiency. Others are non-specific and need further tests to elucidate their etiology (Table 6). Physical examination includes the control of vital parameters, the inspection and palpation for water retention (edema and ascites), and a rough assessment of muscle mass and subcutaneous fat stores.

Clinical signs and symptoms of micronutrient deficiencies

Body Region


Possible Deficiencies



Vitamins A, C


Vitamins C, K




Protein, vitamin B1


Folate, iron, biotin, vitamins B12, B6


Protein, energy

Seborrheic dermatitis

Vitamin B6, biotin, zinc, essential fatty acids

Unhealed wounds

Vitamin C, protein, zinc


Pallor or white coloring

Clubbing, spoon-shape, or transverse ridging/banding; excessive dryness, darkness in nails, curved nail ends

Iron, protein, vitamin B12


Dull/lackluster; banding/sparse; alopecia; depigmentation of hair; scaly/flaky scalp

Protein and energy, biotin, copper, essential fatty acid


Pallor conjunctiva

Vitamin B12, folate, iron

Night vision impairment

Vitamin A



Oral cavity


Vitamins B2, B6, B12, niacin, iron, folate


Vitamin C

Fissures, stomatitis

Vitamin B2, iron, protein


Niacin, vitamins B2, B6, protein

Pale tongue

Iron, vitamin B12

Atrophied papillae

Vitamin B2, niacin, iron

Nervous system

Mental confusion

Vitamins B1, B2, B12, water

Depression, lethargy

Biotin, folate

vitamin C

Weakness, leg paralysis

Vitamins B1, B6, B12, pantothenic acid

Peripheral neuropathy

Vitamins B2, B6, B12


Vitamin B12


Vitamin B1

Muscle cramps

Vitamin B6, calcium, magnesium


Energy, biotin, magnesium, iron

  Compartment models of body composition.

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FFM: fat-free mass, FM: fat mass, BCM: body cell mass, ECM: extracellular cell mass. 

Macronutrient requirements for adults.


Energy Content

Recommended Amount/kg Body Weight/dAY


4 kcal

1.0–1.5 g


4 kcal

max. 3–5 g


9 kcal

0.8–1.5 g


Reber, Emilie et al. “Nutritional Risk Screening and Assessment.” Journal of clinical medicine vol. 8,7 1065. 20 Jul. 2019, doi:10.3390/jcm8071065 https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31330781/ his article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Whole Foods Checklist 

Don't forget a basic checklist of the most important foods to consume:

  • Fruits, including berries, grapes, citrus, olives, etc.

  • Vegetables, including leafy greens, cruciferous vegetables,

    orange/yellow vegetables, onions, garlic, etc.

  • Herbs and spices, including basil, oregano, rosemary, parsley, turmeric, cumin, ginger, etc.

  • Nuts, including almonds, walnuts, pistachios, etc.

  • Seeds, including cacao, chia, flax, pumpkin, hemp, etc.

  • Whole grains as tolerated, including oatmeal, non-GMO corn, etc.

  • Legumes as tolerated, including peanuts, non-GMO soybeans, lentils, black beans, etc.

  • Clean lean protein, including organic poultry and eggs, grass-fed beef and dairy, seafood, etc.

  • Omega-3 sources, including salmon, sardines, and occasionally tuna.

  • Fermented foods, including yogurt, cheese, kefir, sauerkraut, etc.

  • Hydrate with plenty of pure alkalized water and healthy beverages, including organic coffee, tea, homemade alkaline lemon-limeade, etc.

A sustainable Mediterranean-style diet is a healthy choice:

Source: Serra-Majem, Lluís et al. “Updating the Mediterranean Diet Pyramid towards Sustainability: Focus on Environmental Concerns.” International journal of environmental research and public health vol. 17,23 8758. 25 Nov. 2020, doi:10.3390/ijerph17238758. https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/33255721/ This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license
Tag(s): Biomarkers

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