破壞全身血管
內分泌科專科醫生唐俊業指，根據臨床經驗，大部分糖尿病者同時有高血壓及膽固醇超標問題，這與新陳代謝、脂肪分布及胰島素分泌出現毛病有關。
糖尿病可怖之處在於其有機會破壞全身血管，令血管收窄、閉塞，引發冠心病、中風 等嚴重心血管併發症，還會破壞腎功能、視網膜，以及令腳部神經受損致潰爛。
驗血脂及蛋白尿
唐醫生指，除血糖水平外，高血脂及高血壓均可增加心血管疾病的機會。「血脂包括總膽固醇、三酸甘油脂、高密度膽固醇及低密度膽固醇，驗血脂時必須包含以上項目。當中尤以低密度膽固醇水平（俗稱壞膽固醇）最為重要，皆因它是引發心血管病風險的重要成因，與三酸甘油脂一樣，壞膽固醇同樣可靠藥物控制，但必須配合飲食控制及保持適量運動。」唐解釋。
血壓高會加速血管硬化，令表面細胞受破壞及增厚，更易令膽固醇積聚於血管內，增加患上心血管疾病風險。「高血壓及血糖同時破壞腎臟組織結構，易致蛋白流失於尿液中，形成蛋白尿。」他說。
空腹檢驗準確度低
他續稱，只進行空腹血糖檢查，並不能準確檢驗血糖水平是否正常，病人還需要進行口服葡萄糖耐量測試，以確定是否患有前期糖尿，「即使空腹檢查結果顯示血糖無超標，亦不代表血糖水平真的正常，建議病人飲糖水兩小時後再抽血檢驗，正常血糖水平應低於5.5，如數字介乎7.8至11.1，已可被診斷為前期糖尿，表示身體血糖偏高，胰臟功能及血管開始受損，增患心血管疾病的風險。」
服藥與否看血糖數據
早前，英國有研究指，前期糖尿病人服藥後，病情改善效果未如理想，相信嚴控飲食及運動能更有效控制病情，唐醫生表示，戒口及做運動是控制血糖水平的首要條件，然後再根據血糖水平數據，以決定病人是否需要服藥，「如血糖數字接近11，已與患上糖尿病無異，可能有需要配合藥物控制；如數字接近8，會建議病人先控制飲食以及多做運動，再觀察病情反應。」
定量進食
資深營養師黃榮俊指，血糖偏高人士首要控制澱粉質及糖分攝取，依營養師指引，每餐定量攝取不同營養素，「葡萄糖是令血糖上升的主要因素，故病者有需要嚴防澱粉質攝取量，一般情況是每餐一碗或以下，同時間，其他營養素如纖維、脂肪攝取量亦會影響血糖上升速度。由於血脂及血壓過高不利血糖控制，故飲食應以低脂、低糖、低鈉及高纖為原則。」
營養功效對照
| 有益營養素 | 功用 | 有關食物 |
| 水溶性纖維 | 有助減慢血糖上升速度 | 燕麥、豆類、蘋果及士多啤梨等。 |
| 非水溶性纖維 | 吸收壞膽固醇 | 紅米、糙米、西蘭花、芥蘭等。 |
| 茶多酚 | 抗氧化營養素能阻止自由基破壞胰臟細胞，有助預防退化性糖尿病。 | 綠茶 |
| 鉻 | 有助胰島素合成 | 番石榴 |
| 苦瓜素 | 增加胰島素分泌 | 苦瓜 |
| 銀杏脂酮 | 抗氧化功能預防血管硬化及視網膜等病變 | 銀杏 |
■ 運動有助降血糖、減輕胰臟壓力，同時增加高密度膽固醇的水平，保持心血管健康。
■ 藥物阿卡波糖可減低澱粉質於腸道的吸收量，維持血糖水平穩定。
■ 病人及長者應該每年進行併發症檢查。
糖尿病患者忌吃
粥： 由於易消化但亦易吸收，升糖值極高，進食後一小時可由8提升至17，大大提高胰臟負荷，病患者忌吃。
果汁： 纖維量少，果糖含量極高，快速喝下更加快血糖上升。
老火湯： 老火湯及其湯渣的熱量、糖分及脂肪含量極高，易令血糖快速升高。
添加糖： 糖果、甜品及白砂糖等，含有精製糖分，進食後會被迅速吸收，加快血糖上升的速度。
■ 血糖高人士不宜飲用老火湯及粥品。
常見食物升糖指數
澱粉質類
燕麥片
熱量：374kcal/100g
升糖指數：55至63
級別：中級
白麵包
熱量：252kcal/100g
升糖指數：75
級別：高級
全麥麵包
熱量：227kcal/100g
升糖指數：
級別：中級
白米飯
熱量：130kcal/100g
升糖指數：72至83
級別：高級。
糙米飯
熱量：111kcal/100g
升糖指數：48
級別：低級
水煮粉絲
熱量：365kcal/100g
升糖指數：39
級別：低級
如何選擇：經「打磨」的麵飯類，如白飯及上海麵等，可令血糖快速上升，最好以五穀類如紅米、糙米或原粒大麥製品代之。
蔬果類
西瓜
熱量：25kcal/100g
升糖指數：76
級別：高級
黑葡萄
熱量：63kcal/100g
升糖指數：59
級別：中級
蘋果
熱量：52kcal/100g
升糖指數：39
級別：低級
烚薯仔
熱量：62kcal/100g
升糖指數：62
級別：中級
南瓜
熱量：22kcal/100g
升糖指數別：70
級別：高級
粟米
熱量：106kcal/100g
升糖指數：55
級別：低級。
如何選擇：大部分蔬果升糖指數均低，但南瓜及西瓜除外，血糖不穩定人士須小心進食分量。
零食類
爆谷
熱量：30kcal/一杯
升糖指數：55
級別：低級
薯片
熱量：249kcal/100g
升糖指數：60
級別：中級
梳打餅
熱量：119kcal/6塊
升糖指數：70
級別：高級
可樂
熱量：150kcal/一罐
升糖指數：58
級別：中級
香蕉奶昔
熱量：155kcal/一杯
升糖指數：30
級別：低級
杏脯乾
熱量：110kcal/30g
升糖指數：31
級別：低級
如何選擇：部分低GI零食含高飽和脂肪，如香蕉奶昔、薯片等。看似健怡的梳打餅及白麵包其實GI甚高，勿掉以輕心。
註：食物升糖指數級別及數值：低GI—GI在55或以下、中GI—GI介乎56至69、高GI—GI在70或以上（GI100為最高，如葡萄糖。）
參考資料：www.glycemicindex.com
嚴控三高新品 防血管病變
高血糖、高膽固醇及高血壓（俗稱三高），乃心血管疾病誘因之一。專科醫生提
醒，除藥物治療外，自行監控血壓，對病情控制十分重要。而有關監測新品日新月異，方便易用，有助患者自控及醫生評估健康狀況。
男性患者較多
據心臟專科醫生李沛然（上圖）指，隨年齡增長、城市人工作壓力大、少做運動，常外出用膳以致攝取過量脂肪、糖分及鹽分，再加上吸煙和飲酒，令患上「三高」人士愈來愈多，大大增患心血管疾病的風險，「『三高』可引致動脈粥狀硬化，當脂肪及膽固醇攝取過量，部分有機會聚積於血管內壁，久而久之形成脂肪斑瑰，令血管內壁愈變愈厚，血管通道收窄，易致各種心血管疾病如冠心病、中風等。」他續稱早期冠心病可毫無病徵，病發時卻可致命，發病年齡平均50歲以上，男性居多，但近年30至40歲患者有上升趨勢。
糖尿病者高危
李醫生又提醒糖尿病患者：「血液糖分高會增加血管發炎機會，加速或提早血管出現硬化，糖尿病者80%死因與心血管疾病有關。病者除用藥物控制血糖外，還要嚴格監控飲食，多做運動以減低心血管病風險。」
膽固醇分為高密度的好膽固醇、低密度膽固醇的壞膽固醇，以及三酸甘油脂三種，而低密度膽固醇過高乃導致心血管病一項重要因素，「高密度膽固醇含量高有利心血管健康，故評估心血管疾病風險時，不能單看總膽固醇水平。另有研究指，30%至40%心臟病人甚至沒有壞膽固醇高的問題，這反映了膽固醇高只是其中一個致病因素。醫生會替病人作出風險評估，再決定是否處方藥物，例如是否患有心臟病、高血壓、糖尿病及中央肥胖，以及年齡、膽固醇超標程度等作考慮因素。」李醫生說。
每天量血壓
血壓高令血管壁壁受壓力增加，除易致血管受損及硬化，更增加出現心臟衰竭、中風、眼底出血及腎衰竭的機會。由於沒有明顯徵狀，患者必須定期量血壓，控制血壓維持於正常水平︰正常為上壓低於120mmHg，同時下壓低於80mmHg。而高血壓前期即患上心血管疾病風險，較正常人士高者，其上壓為120mmHg至140mmHg或下壓為80至90mmHg。高血壓人士，即上壓高於140mmHg或下壓高過90mmHg。
應自行監察
李醫生又稱，電子血壓計使用方便、準確度高，他建議病人每天使用，以自行監察血壓水平並把數字記低，覆診時給醫生跟進，「部分病人見到醫護人員時血壓會上升，稱為『白袍高血壓』，故平日在家量度數字可能更準確。已患有糖尿病、腎衰竭及心血管病人士，更需要較一般患者嚴格控制血壓，以減少併發症風險。」
量血壓前，應至少有五至十分鐘休息，在平靜心情或舒適環境下進行，早晚各一次。之前避免進行刺激性活動，包括運動、喝茶、咖啡及洗澡，亦不應躺臥進行。
Evidence-Based Nutrition Principles and Recommendations for the Treatment and Prevention of Diabetes and Related Complications
American Diabetes Association
http://care.diabetesjournals.org/content/25/1/202.full#sec-4
Medical nutrition therapy is an integral component of diabetes management and of diabetes self-management education. Yet many misconceptions exist concerning nutrition and diabetes. Moreover, in clinical practice, nutrition recommendations that have little or no supporting evidence have been and are still being given to persons with diabetes. Accordingly, this position statement provides evidence-based principles and recommendations for diabetes medical nutrition therapy. The rationale for this position statement is discussed in the American Diabetes Association technical review “Evidence-Based Nutrition Principles and Recommendations for the Treatment and Prevention of Diabetes and Related Complications,” which discusses in detail the published research for each principle and recommendation (1).
Historically, nutrition recommendations for diabetes and related complications were based on scientific knowledge, clinical experience, and expert consensus; however, it was often difficult to discern the level of evidence used to construct the recommendations. To address this problem, the 2002 technical review (1) and this position statement provide principles and recommendations classified according to the level of evidence available using the American Diabetes Association evidence grading system. However, the best available evidence must still take into account individual circumstances, preferences, and cultural and ethnic preferences, and the person with diabetes should be involved in the decision-making process. The goal of evidence-based recommendations is to improve diabetes care by increasing the awareness of clinicians and persons with diabetes about beneficial nutrition therapies.
Because of the complexity of nutrition issues, it is recommended that a registered dietitian, knowledgeable and skilled in implementing nutrition therapy into diabetes management and education, be the team member providing medical nutrition therapy. However, it is essential that all team members be knowledgeable about nutrition therapy and supportive of the person with diabetes who needs to make lifestyle changes.
GOALS OF MEDICAL NUTRITION THERAPY FOR DIABETES
Goals of medical nutrition therapy that apply to all persons with diabetes are as follows:
1. Attain and maintain optimal metabolic outcomes including
l Blood glucose levels in the normal range or as close to normal as is safely possible to prevent or reduce the risk for complications of diabetes.
l A lipid and lipoprotein profile that reduces the risk for macrovascular disease.
l Blood pressure levels that reduce the risk for vascular disease.
2. Prevent and treat the chronic complications of diabetes. Modify nutrient intake and lifestyle as appropriate for the prevention and treatment of obesity, dyslipidemia, cardiovascular disease, hypertension, and nephropathy. 3. Improve health through healthy food choices and physical activity. 4. Address individual nutritional needs taking into consideration personal and cultural preferences and lifestyle while respecting the individual’s wishes and willingness to change.
Goals of medical nutrition therapy that apply to specific situations include the following:
1. For youth with type 1 diabetes, to provide adequate energy to ensure normal growth and development, integrate insulin regimens into usual eating and physical activity habits.
2. For youth with type 2 diabetes, to facilitate changes in eating and physical activity habits that reduce insulin resistance and improve metabolic status.
3. For pregnant and lactating women, to provide adequate energy and nutrients needed for optimal outcomes.
4. For older adults, to provide for the nutritional and psychosocial needs of an aging individual.
5. For individuals treated with insulin or insulin secretagogues, to provide self-management education for treatment (and prevention) of hypoglycemia, acute illnesses, and exercise-related blood glucose problems.
6. For individuals at risk for diabetes, to decrease risk by encouraging physical activity and promoting food choices that facilitate moderate weight loss or at least prevent weight gain.
MEDICAL NUTRITION THERAPY FOR TYPE 1 AND TYPE 2 DIABETES
Carbohydrate and diabetes
When referring to common food carbohydrates, the following terms are preferred: sugars, starch, and fiber. Terms such as simple sugars, complex carbohydrates, and fast-acting carbohydrates are not well defined and should be avoided. Studies in healthy subjects and those at risk for type 2 diabetes support the importance of including foods containing carbohydrate particularly from whole grains, fruits, vegetables, and low-fat milk in the diet of people with diabetes.
A number of factors influence glycemic responses to foods, including the amount of carbohydrate, type of sugar (glucose, fructose, sucrose, lactose), nature of the starch (amylose, amylopectin, resistant starch), cooking and food processing (degree of starch gelantinization, particle size, cellular form), and food form, as well as other food components (fat and natural substances that slow digestion—lectins, phytates, tannins, and starch-protein and starch-lipid combinations). Fasting and preprandial glucose concentrations, the severity of glucose intolerance, and the second meal or lente effect of carbohydrate are other factors affecting the glycemic response to foods. However, in persons with type 1 or type 2 diabetes, ingestion of a variety of starches or sucrose, both acutely and for up to 6 weeks, produced no significant differences in glycemic response if the amount of carbohydrate was similar. Studies in controlled settings and studies in free-living subjects produced similar results. Therefore, the total amount of carbohydrate in meals and snacks will be more important than the source or the type.
Studies in subjects with type 1 diabetes show a strong relationship between the premeal insulin dose and the postprandial response to the total carbohydrate content of the meal. Therefore, the premeal insulin doses should be adjusted for the carbohydrate content of the meal. For individuals receiving fixed doses of insulin, day-to-day consistency in the amount of carbohydrate is important.
In persons with type 2 diabetes, on weight maintenance diets, replacing carbohydrate with monounsaturated fat reduces postprandial glycemia and triglyceridemia. However, there is concern that increased fat intake in ad libitum diets may promote weight gain. Therefore, the contributions of carbohydrate and monounsaturated fat to energy intake should be individualized based on nutrition assessment, metabolic profiles, and treatment goals.
Glycemic index.
Although low glycemic index diets may reduce postprandial glycemia, the ability of individuals to maintain these diets long-term (and therefore achieve glycemic benefit) has not been established. The available studies in persons with type 1 diabetes in which low glycemic index diets were compared with high glycemic index diets (study length from 12 days to 6 weeks) do not provide convincing evidence of benefit. In subjects with type 2 diabetes, studies of 2–12 weeks duration comparing low glycemic index and high glycemic index diets report no consistent improvements in HbA1c, fructosamine, or insulin levels. The effects on lipids from low glycemic index diets compared with high glycemic index diets are mixed.
Although it is clear that carbohydrates do have differing glycemic responses, the data reveal no clear trend in outcome benefits. If there are long-term effects on glycemia and lipids, these effects appear to be modest. Moreover, the number of studies is limited, and the design and implementation of several of these studies is subject to criticism.
Fiber.
As for the general population, people with diabetes are encouraged to choose a variety of fiber-containing foods, such as whole grains, fruits, and vegetables because they provide vitamins, minerals, fiber, and other substances important for good health. Early short-term studies using large amounts of fiber in small numbers of subjects with type 1 diabetes suggested a positive effect on glycemia. Recent studies have reported mixed effects on glycemia and lipids. In subjects with type 2 diabetes, it appears that ingestion of very large amounts of fiber are necessary to confer metabolic benefits on glycemic control, hyperinsulinemia, and plasma lipids. It is not clear whether the palatability and the gastro-intestinal side effects of fiber in this amount would be acceptable to most people.
Sweeteners.
The available evidence from clinical studies demonstrates that dietary sucrose does not increase glycemia more than isocaloric amounts of starch. Thus, intake of sucrose and sucrose-containing foods by people with diabetes does not need to be restricted because of concern about aggravating hyperglycemia. Sucrose should be substituted for other carbohydrate sources in the food/meal plan or, if added to the food/meal plan, adequately covered with insulin or other glucose-lowering medication. Additionally, intake of other nutrients ingested with sucrose, such as fat, need to be taken into account.
In subjects with diabetes, fructose produces a lower postprandial response when it replaces sucrose or starch in the diet; however, this benefit is tempered by concern that fructose may adversely effect plasma lipids. Therefore, the use of added fructose as a sweetening agent is not recommended; however, there is no reason to recommend that people with diabetes avoid naturally occurring fructose in fruits, vegetables, and other foods.
Sugar alcohols produce a lower postprandial glucose response than fructose, sucrose, or glucose and have lower available energy values. However, there is no evidence that the amounts likely to be consumed in a meal or day result in a significant reduction in total daily energy intake or improvement in long-term glycemia. The use of sugar alcohols appears to be safe; however, they may cause diarrhea, especially in children.
The Food and Drug Administration has approved four non-nutritive sweeteners for use in the U.S.—saccharin, aspartame, acesulfame potassium, and sucralose. Before being allowed on the market, all underwent rigorous scrutiny and were shown to be safe when consumed by the public, including people with diabetes and during pregnancy.
RESISTANT STARCH
It has been proposed that foods containing naturally occurring resistant starch (cornstarch) or foods modified to contain more resistant starch (high amylose cornstarch) may modify postprandial glycemic response, prevent hypoglycemia, reduce hyperglycemia, and explain differences in the glycemic index of some foods. However, there are no published long-term studies in subjects with diabetes to prove benefit from the use of resistant starch.
RECOMMENDATIONS
A-Level evidence
1. Foods containing carbohydrate from whole grains, fruits, vegetables, and low-fat milk should be included in a healthy diet.
2. With regard to the glycemic effects of carbohydrates, the total amount of carbohydrate in meals or snacks is more important than the source or type.
3. As sucrose does not increase glycemia to a greater extent than isocaloric amounts of starch, sucrose and sucrose-containing foods do not need to be restricted by people with diabetes; however, they should be substituted for other carbohydrate sources or, if added, covered with insulin or other glucose-lowering medication.
4 . Non-nutritive sweeteners are safe when consumed within the acceptable daily intake levels established by the Food and Drug Administration.
B-Level evidence
1. Individuals receiving intensive insulin therapy should adjust their premeal insulin doses based on the carbohydrate content of meals.
2. Although the use of low glycemic index foods may reduce postprandial hyperglycemia, there is not sufficient evidence of long-term benefit to recommend use of low glycemic index diets as a primary strategy in food/meal planning.
3. As with the general public, consumption of dietary fiber is to be encouraged; however, there is no reason to recommend that people with diabetes consume a greater amount of fiber than other Americans.
C-Level evidence
1. Individuals receiving fixed daily insulin doses should try to be consistent in day-to-day carbohydrate intake.
Expert consensus
1. Carbohydrate and monounsaturated fat together should provide 60–70% of energy intake. However, the metabolic profile and need for weight loss should be considered when determining the monounsaturated fat content of the diet.
2. Sucrose and sucrose-containing foods should be eaten in the context of a healthy diet.
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