PROTEIN Dr Annis Catur Adi Dept Gizi Kesehatan

PROTEIN Dr. Annis Catur Adi Dept Gizi Kesehatan Fakultas Kesehatan Masyarakat Universitas Airlangga

l l Protein ditemukan didlm setial sel. Protein berasal (bahasa Yunani): “Primary, holding first place” yg berarti menduduki tempat yang terutama. Protein adalah penting bagian sel-sel Protein disusun dari unsur carbon, hydrogen, oxygen, and nitrogen , yg dibentuk kedalam “basic unit” dinamakan amino acids. Terdapat 20 AA. 8 -10 macam essensial, harus dibentuk dari luar tubuh (bentuk jadi dari makanan sehari-hari) Complete proteins Incomplete proteins Legumes

Ada 8 AA esensial untuk org dewasa (Isoleusin, Lisin, Metionin, Fenilalanin, Treonin, Triptofan dan Valin), dan 10 AA esensial pada anak -anak ( 8 AA + arginin dan histidin) Jenis protein menurut AA: l Complete protein : protein yg mengandung AA esensial lengkap (jumlah & jenisnya). Berasal sumber hewani. Contoh: Kasein pd susu, Albumin pd putih telur l Incomplete/Partiallly complete protein : protein yg tdk mengandung AA esensial atau sedikit. Berasal sumber nabati. Contoh Zein pada jagung dan protein nabati lainnya. l Partiallly complete protein : protein yg mengandung AA esensial lengkap, tetapi beberapa diantaranya hanya sedikit. Contoh Legumin pada kacangan-kacangan, Gliadin pd gandum, dll l

Fungsi of Protein Pertumbuhan dan pemeliharaan Jar. Tubuh Protein sbg bhn pembangun jar. baru. Sbg zat pembangun: bagian inti sel, bagian padat jaringan dlm tubuh (otot, sel-2/butir darah), bagian enzim, hormon, antibodi, dll. l Protein sebagai pengatur: kelangsungan proses-proses di dlm tubuh. Hormon, enzim, tekanan osmosis, keseimbangan p. H l Protein sebagai bahan bakar: mengandung karbon. Mensuplai 4 Kal/gram, scr ekonomi sumber energi yg mahal drpd KH dan Lemak. Kecukupan: 10 -15% tot Kal. = 210 Kal = 52, 5 g l

Sumber protein l l Protein dgn nilai biological tinggi, terutama pd pangan hewani: daging, ikan, telur, keju dan susu. . Protein dgn nilai Biological rendah, terutama berasal dari: pangan nabati: kacangan, polong, sereal, dll

Metabolisme l l l 15% - 20% diet seharusnya dari protein Pencernaan protein: pecah menjadi asam amino (dilambung), diserap dinding usus halus. ( 60% diserap usus halus atas, 28 % di usus besar dan 12 % telah mulai dilambung). Faktor yg pengaruhi kebutuhan protein : 1) BB, 2) Umur dan jenis kelamin (anak kecil 4 x dewasa), 3) Mutu protein (nilai cerna dan serap), dan 4) Pertumbuhan

Nitrogen balance and protein requirements Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation ©

Nitrogen balance and protein requirements In children who are growing, the need for dietary protein is obvious Why does an adult, who is not growing require a dietary intake of protein ? Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation ©

An overview of protein metabolism dietary protein 80 g enzymes intestinal cells mucus 70 g amino acids dipeptides body protein ~ 10 kg amino acids metabolites fecal loss (10 g) Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © urine excretion (70 g)

Urinary N metabolites urea 10 – 35 g /day ammonium ions 340 – 1200 mg /day amino acids 1. 3 – 3. 2 g /day uric acid 250 – 750 mg /day creatinine women 1. 2, men 1. 8 g /day creatine < 50 mg /day Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © copyright David A Bender 2007

Nitrogen balance = intake - excretion intake = excretion intake > excretion intake < excretion dietary protein 80 g enzymes intestinal cells mucus 70 g amino acids dipeptides body protein ~ 10 kg amino acids metabolites fecal loss (10 g) Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © urine excretion (70 g)

Nitrogen balance = intake - excretion INTAKE = EXCRETION N balance or equilibrium normal state in an adult no change in body protein content dietary protein 80 g enzymes intestinal cells mucus 70 g amino acids dipeptides body protein ~ 10 kg amino acids metabolites fecal loss (10 g) Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © urine excretion (70 g)

Nitrogen balance = intake - excretion INTAKE > EXCRETION positive N balance or equilibrium increase in body protein content normal in growth, pregnancy and recovery from loss dietary protein 80 g enzymes intestinal cells mucus 70 g amino acids dipeptides body protein ~ 10 kg amino acids metabolites fecal loss (10 g) Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © urine excretion (70 g)

Nitrogen balance = intake - excretion INTAKE < EXCRETION negative N balance decrease in body protein content never normal; indicates illness, trauma or inadequate intake dietary protein 80 g enzymes intestinal cells mucus 70 g amino acids dipeptides body protein ~ 10 kg amino acids metabolites fecal loss (10 g) Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © urine excretion (70 g)

N balance: determination of protein requirements Several studies show the average requirement = 0. 66 g /kg body weight Safe and adequate level of intake = 0. 825 g /kg body weight (UK average = 1. 2) Safe and adequate level of intake = 8% of energy intake (UK average = 15) Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © copyright David A Bender 2007

Protein deficiency is unlikely in an adult Safe and adequate protein intake is 8. 25 % of energy intake If you can eat enough of most “starchy” staples to meet energy needs you will meet your protein requirements Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation ©

Protein turnover in the fed and fasting states mmol /hour synthesis catabolism fed 8. 8 8. 1 fasting 6. 4 7. 85 In the fasting state amino acids from protein breakdown are being used for gluconeogenesis and as metabolic fuel In the fed state there is an ample energy supply to permit protein synthesis Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation ©

Percentage of energy expenditure at rest Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation ©

The fed state – ample fuels entering from the gut glycogen triacyglycerol protein glucose triacylglycerol in VLDL amino acids glucose glycogen protein amino acids Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © triacylglycerol in chylomicrons

The fasting state – utilization of body reserves amino acids glucose triacyglycerol protein ketone bodies glucose amino acids hormone-sensitive lipase glycerol fatty acids glycogen Introduction to Nutrition and Metabolism, 4 th edition, CRC Press, Boca Raton. Presentation © fatty acids

Ringkasan Protein l l Protein : zat pembangun tubuh. Pembentukan jaringan dan memelihara kesehatan tubuh. Sumber protein: hewani dan nabati Mutu protein hewani lbh tinggi dari nabati Mutu protein dpt ditingkatkan dengan: * mengkonsumsi berbagai protein * menambah ikan, telur, daging meski hanya sedikit

Ringkasan Protein (keseimbangan N)

Annis CA/ Dept Gizi Kesmas/ FKM-UA