Diet, nutrition and excretion of the Asiatic races in Singapore
J. Argyll Campbell, a physician practising in Singapore, published this comparative study in 1917 presenting weighed-diet and 24-hour urine excretion data from four medical students of different ethnic backgrounds (Chinese, Tamil, Malay, and Brahmin) over periods ranging from two weeks to six months. The overarching thesis is that European reference values for renal excretion are clinically useless when applied to Asiatic patients, and that the tropical climate of Singapore directly reduces caloric and protein requirements compared with both European and other tropical settings.
Summary
Campbell’s study addresses a practical clinical problem: the absence of locally relevant physiological norms for patients in the Straits Settlements. By placing four medical students on their own freely chosen diets and collecting preserved 24-hour urine specimens, he generated baseline figures for ammonia, chloride, urea, total nitrogen, and specific gravity that could be compared against published European data (Ranke) and tropical data from Bengal (McCay) and the Philippines (Aron). The methodological approach was straightforward clinical chemistry—Cramer’s quantitative analyses, Kjeldahl nitrogen estimation, Volhard’s chloride titration, and the Doremus-Heinz ureometer—acknowledged by Campbell as approximate but sufficient for clinical purposes.
The central argument proceeds from the observation that all four Asiatic students consumed substantially less protein and fewer total kilocalories than the European reference subject, and that their renal excretion figures reflected this reduced intake rather than any inherent racial metabolic difference. The Brahmin, a strict vegetarian, consumed the most protein by weight (83 g) yet metabolised the least (41.5 g), which Campbell attributes to the bulk and indigestibility of his vegetable diet rather than to any constitutional inferiority. The Chinese student, by contrast, metabolised 57.8 g of his 60 g protein intake, indicating efficient utilisation. Campbell then situates these findings climatically: Singapore’s constant 80°F temperature and high humidity reduce heat loss and therefore caloric need, explaining why Singapore students eat less than their Bengali or Filipino counterparts who experience seasonal variation.
A secondary thread concerns the clinical implications for tropical medicine. Campbell argues that the free diaphoresis of the tropics means fluid intake is insufficient to flush the kidneys adequately, so excess food materials tax the excretory organs and can cause cumulative organ damage. He notes that Europeans in the tropics must exercise to maintain health on a European diet, while the local students’ smaller intakes may represent “nature’s way of counteracting the evil effects of the climate.” He also observes that intellectual work imposes no measurable metabolic cost, so the students’ academic performance is not compromised by their smaller diets.
Key Findings
- The Chinese student’s average six-month diet supplied 1,577 kcal (60 g protein, 43 g fat, 227 g carbohydrate); the Brahmin’s vegetarian diet supplied 2,493 kcal (83 g protein, 68 g fat, 371 g carbohydrate) but only half the protein was metabolised (p. 58, Table II).
- Total nitrogen excretion ranged from 6.64 g (Brahmin) to 9.25 g (Chinese) per diem, compared with 16 g for the European reference; urea ranged from 11.08 g to 16.00 g versus 35 g for the European (Table I, p. 60).
- The ammonia coefficient (ammonia nitrogen as a percentage of total nitrogen) was 5.4% for the Chinese and 7.1% for the Brahmin, compared with 3.6% for the European, reflecting the lower total nitrogen excretion in the Asiatic subjects (Table I, p. 60).
- Chloride excretion was 5.21–8.00 g for the Asiatic students versus 11.00 g for the European, which Campbell links to the higher vegetable (potassium-rich) proportion in their diets (pp. 59–60).
- The Singapore students consumed fewer kilocalories than the Bengali student (3,196 kcal) or the Filipino student (2,632 kcal), which Campbell attributes to Singapore’s lack of seasonal temperature variation and its higher humidity (pp. 61–62).
- Campbell’s own urine analysis in Singapore showed an ammonia excretion of 1.06 g (versus 0.70 g in Europe) and chloride of 8.10 g, indicating that even a European resident on a Scottish-style diet exhibits altered excretion in the tropical climate (Table I, p. 60).
Conclusion
Campbell’s definitive takeaway is that European physiological constants cannot be transplanted to the clinical assessment of Asiatic patients in the tropics. The lower renal excretion figures observed in his subjects are explained by lower protein intake and climatic reduction of caloric need, not by any fixed racial metabolic type. He further warns that prolonged residence in a Singapore-like climate is incompatible with the maintenance of European-level muscular energy, since the reduced protein intake necessary for health in such conditions limits the substrate available for muscle metabolism.
Context
- Campbell was a practising physician in Singapore with nine years’ experience teaching European students and four years with local students; the study draws on his own clinical observations and his personal urine analysis as a European control (p. 62).
- The article is the first in a series (“No. 1, Medical Students”), suggesting further volumes covering other populations (e.g., coolies) were planned. Its historiographical value lies in providing one of the earliest quantitative tropical metabolic datasets from the Straits Settlements, predating the more systematic nutritional surveys of the 1930s.